Publications | Xavier Gonze's research group

Xavier Gonze’s google scholar page is here.

Publications prior 2012 are not mentioned in this list.

2023

V. Brousseau-Couture, X. Gonze, and M. Côté, « Effect of spin-orbit coupling on the zero-point renormalization of the electronic band gap in cubic materials: First-principles calculations and generalized Fröhlich model, » Physical Review B, vol. 107, iss. 11, p. -, 2023.
[Bibtex]

@article{brousseau2023,
title = {{Effect of spin-orbit coupling on the zero-point renormalization of the electronic band gap in cubic materials: First-principles calculations and generalized Fr{\"o}hlich model}},
author = {Brousseau-Couture, V�ronique and Gonze, Xavier and C{\^o}t{\'e}, Michel},
abstract = {The electronic structure of semiconductors and insulators is affected by ionic motion through electron-phonon interaction, yielding temperature-dependent band gap energies and zero-point renormalization (ZPR) at absolute zero temperature. For polar materials, the most significant contribution to the band gap ZPR can be understood in terms of the Fr�hlich model, which focuses on the non-adiabatic interaction between an electron and the macroscopic electrical polarization created by a long-wavelength optical longitudinal phonon mode. On the other hand, spin-orbit interaction (SOC) modifies the bare electronic structure, which will, in turn, affect the electron-phonon interaction and the ZPR. We present a comparative investigation of the effect of SOC on the band gap ZPR of twenty semiconductors and insulators with cubic symmetry using first-principles calculations. We observe a SOC-induced decrease of the ZPR, up to 30%, driven by the valence band edge, which almost entirely originates from the modification of the bare electronic eigenenergies and the decrease of the hole effective masses near the G point. We also incorporate SOC into a generalized Fr�hlich model, addressing the Dresselhaus splitting which occurs in non-centrosymmetric materials, and confirm that the predominance of non-adiabatic effects on the band gap ZPR of polar materials is unchanged when including SOC. Our generalized Fr�hlich model with SOC provides a reliable estimate of the SOC-induced decrease of the polaron formation energy obtained from first principles and brings to light some fundamental subtleties in the numerical evaluation of the effective masses with SOC for non-centrosymmetric materials. We finally warn about a possible breakdown of the parabolic approximation, one of the most fundamental assumptions of the Fr�hlich model, within the physically relevant energy range of the Fr�hlich interaction for materials with high phonon frequencies treated with SOC.},
Keywords = {IMCN/MODL},
language = {Anglais},
journal = {{Physical Review B}},
volume = {107},
number = {11},
pages = {-},
issn = {2469-9969},
doi = {10.1103/physrevb.107.115173},
publisher = {American Physical Society (APS)},
year = {2023},
url = {http://hdl.handle.net/2078.1/276846}}

C. Tantardini, A. G. Kvashnin, M. Azizi, X. Gonze, C. Gatti, T. Altalhi, and B. I. Yakobson, « Electronic Properties of Functionalized Diamanes for Field-Emission Displays, » ACS Applied Materials & Interfaces, vol. 15, iss. 12, pp. 16317-16326, 2023.
[Bibtex]

@article{tantardini2023,
title = {{Electronic Properties of Functionalized Diamanes for Field-Emission Displays}},
author = {Tantardini, Christian and Kvashnin, Alexander G. and Azizi, Maryam and Gonze, Xavier and Gatti, Carlo and Altalhi, Tariq and Yakobson, Boris I.},
abstract = {Ultrathin diamond films, or diamanes, are promising quasi-2D materials that are characterized by high stiffness, extreme wear resistance, high thermal conductivity, and chemical stability. Surface functionalization of multilayer graphene with different stackings of layers could be an interesting opportunity to induce proper electronic properties into diamanes. Combination of these electronic properties together with extraordinary mechanical ones will lead to their applications as field-emission displays substituting original devices with light-emitting diodes or organic light-emitting diodes. In the present study, we focus on the electronic properties of fluorinated and hydrogenated diamanes with (111), (110), (0001), (101�0), and (2�110) crystallographic orientations of surfaces of various thicknesses by using first-principles calculations and Bader analysis of electron density. We see that fluorine induces an occupied surface electronic state, while hydrogen modifies the occupied bulk state and also induces unoccupied surface states. Furthermore, a lower number of layers is necessary for hydrogenated diamanes to achieve the convergence of the work function in comparison with fluorinated diamanes, with the exception of fluorinated (110) and (2�110) films that achieve rapid convergence and have the same behavior as other hydrogenated surfaces. This induces a modification of the work function with an increase of the number of layers that makes hydrogenated (2�110) diamanes the most suitable surface for field-emission displays, better than the fluorinated counterparts. In addition, a quasi-quantitative descriptor of surface dipole moment based on the Tantardini�Oganov electronegativity scale is introduced as the average of bond dipole moments between the surface atoms. This new fundamental descriptor is capable of predicting a priori the bond dipole moment and may be considered as a new useful feature for crystal structure prediction based on artificial intelligence.},
Keywords = {IMCN/MODL , General Materials Science},
language = {Anglais},
journal = {{ACS Applied Materials & Interfaces}},
volume = {15},
number = {12},
pages = {16317-16326},
issn = {1944-8252},
doi = {10.1021/acsami.3c01536},
publisher = {{American Chemical Society (ACS)}},
year = {2023},
url = {http://hdl.handle.net/2078.1/276847}}

I. Guster, V. Vasilchenko, M. Azizi, M. Giantomassi, and X. Gonze, « Large cylindrical polaron in orthorhombic SnSe: A theoretical study, » Physical Review Materials, vol. 7, iss. 6, p. 64604, 2023.
[Bibtex]

@article{guster2023,
title = {{Large cylindrical polaron in orthorhombic SnSe: A theoretical study}},
author = {Guster, Ionel-Bogdan and Vasilchenko, Vasilii and Azizi, Maryam and Giantomassi, Matteo and Gonze, Xavier},
abstract = {Due to its phenomenal thermoelectric properties, SnSe has received increased interest, triggering systematic studies of both electronic and vibrational properties and the associated coupling. Recent experimental work claims that orthorhombic SnSe sustains a one-dimensional large polaron with a dimension of about 2 nm. In search of its theoretical signature, we first establish the level of precision that can be reached in describing the electronic structure of SnSe by means of ab initio density functional and many-body perturbation theories. As the characterization of band extrema by means of effective masses plays a crucial role in determining polaron properties, we signal the existence of a broad variation of such quantity among the various ab initio methodologies employed and in the available experimental data. The impact of electron-phonon coupling is then analyzed by employing the recently developed generalized Fr�hlich model as well as the nonadiabatic Allen-Heine-Cardona formalism, and their relative accuracy is rationalized. We found that, although the vast majority of band extrema in SnSe cannot sustain a large one-dimensional polaron with a radius as small as 2 nm, there is one case in which another type of polaron emerges, indeed one-dimensional, but with an unusual oscillating electronic density of an approximate real space period of ~3 nm that evokes a stack of disks. Such type of polaron is obtained from two theoretical treatments: a fixed Gaussian ansatz for the polaron wave function and a variational approach, both within the Fr�hlich formalism. We hypothesize that such cylindrical polaron might be found in other materials with extended, shallow double-well band extrema.},
Keywords = {IMCN/MODL , CISM:CECI , Physics and Astronomy (miscellaneous) , General Materials Science},
language = {Anglais},
journal = {{Physical Review Materials}},
volume = {7},
number = {6},
pages = {064604},
issn = {2475-9953},
doi = {10.1103/physrevmaterials.7.064604},
publisher = {{American Physical Society (APS)}},
year = {2023},
url = {http://hdl.handle.net/2078.1/276854}}

J. W. Zwanziger, M. Torrent, and X. Gonze, « Orbital magnetism and chemical shielding in the projector augmented-wave formalism, » Physical Review B, vol. 107, iss. 16, p. -, 2023.
[Bibtex]

@article{zwanziger2023,
title = {{Orbital magnetism and chemical shielding in the projector augmented-wave formalism}},
author = {Zwanziger, J. W. and Torrent, M. and Gonze, Xavier},
abstract = {We show how to compute the orbital magnetization, as the first-order change of the energy due to an homogeneous magnetic field, within the projector augmented-wave (PAW) formalism of density functional theory, for systems with periodic boundary conditions. To accomplish this, magnetic translation symmetry is invoked together with a perturbative treatment of the density operator, yielding well-posed expressions that account fully for all PAW terms. The terms may be computed in a standard PAW implementation using density functional perturbation theory to compute the necessary wavefunction derivatives, rather than the finite difference approach that has been used previously. In order to obtain nontrivial magnetization, we also impose nuclear magnetic dipole moments on atomic sites of interest, which gives direct access to the chemical shielding, as measured in nuclear magnetic resonance spectroscopy. The resulting expressions have been implemented and tested, and results are shown both for atoms and solids.},
Keywords = {IMCN/MODL},
language = {Anglais},
journal = {{Physical Review B}},
volume = {107},
number = {16},
pages = {-},
issn = {2469-9969},
doi = {10.1103/physrevb.107.165157},
publisher = {{American Physical Society (APS)}},
year = {2023},
url = {http://hdl.handle.net/2078.1/276853}}

2022

C. Tantardini, S. Kokott, X. Gonze, S. V. Levchenko, and W. A. Saidi, « Self-trapping » in solar cell hybrid inorganic-organic perovskite absorbers, » Applied Materials Today, vol. 26, iss. -, p. 101380, 2022.
[Bibtex]

@article{tantardini2022,
title = {Self-trapping" in solar cell hybrid inorganic-organic perovskite absorbers},
author = {Tantardini, Christian and Kokott, Sebastian and Gonze, Xavier and Levchenko, Sergey V. and Saidi, Wissam A.},
abstract = {In the simplest picture, a "self-trapped" polaron forms when an excess electron or hole deforms a crystal lattice, creating a potential well with bound states. Properties of self-trapped polarons in methylammonium lead iodide perovskite (MAPbI3), which is widely used as solar cell absorber, are of great interest, and are a subject of ongoing investigations and debates concerning the existence of large polarons with the co-presence of metastable self-trapping. Herein, we employ a self-interaction-free density functional theory method to investigate the stability of small polarons in tetragonal MAPbI3 phase. The electron small polaron is found to be unstable, while the hole small polaron is found to be metastable at realistic operation temperatures of solar cells. Further, the hole polaron is found to have a hole band close to the conduction band, which in conjunction with its metastability suggests that small polarons will have an appreciable effect on charge-carrier recombinations in MAPbI3. Further, we posit that the existence of the metastable polarons in addition to the large polarons may explain the experimentally observed non-monotonic temperature dependence of bimolecular charge-carrier recombination rate in tetragonal MAPbI3 phase.},
Keywords = {IMCN/MODL , General Materials Science},
language = {Anglais},
journal = {{Applied Materials Today}},
volume = {26},
number = {-},
pages = {101380},
issn = {2352-9407},
doi = {10.1016/j.apmt.2022.101380},
publisher = {Elsevier BV},
year = {2022},
url = {http://hdl.handle.net/2078.1/269453}}

V. Brousseau-Couture, E. Godbout, M. Côté, and X. Gonze, « Zero-point lattice expansion and band gap renormalization: Grüneisen approach versus free energy minimization, » Physical Review B, vol. 106, iss. 8, p. 85137, 2022.
[Bibtex]

@article{brousseau2022,
title = {{Zero-point lattice expansion and band gap renormalization: Gr{\"u}neisen approach versus free energy minimization}},
author = {Brousseau-Couture, V�ronique and Godbout, Emile and C{\^o}t{\'e}, Michel and Gonze, Xavier},
abstract = {The zero-point lattice expansion (ZPLE) is a small variation of the lattice parameters induced by the presence of phonons in a material compared to the static lattice picture. It contributes significantly to the zero-point renormalization (ZPR) of the band gap energy, but its consequences have not been investigated as thoroughly as those stemming from electron-phonon interactions. In the usual first-principles approach, one evaluates the ZPLE by minimizing the T = 0 K Helmholtz free energy. In this work, we show that the formalism based on the Gr�neisen parameters, which commonly neglects zero-point effects, can be efficiently used to compute ZPLE for both isotropic and anisotropic materials at much lower computational cost. We systematically test this formalism on 22 cubic and wurtzite materials and obtain excellent agreement with free energy minimization results for both the ZPLE and the resulting band gap ZPR. We use our results to validate an empirical expression estimating the ZPLE-induced ZPR and unveil its sensitivity to the temperature range involved in estimating the ZPLE from experimental data. Our findings finally reveal that the ZPLE contribution to the band gap ZPR can reach 20% to more than 80% of the electron-phonon interaction contribution for heavier or more ionic materials, including materials containing light atoms. Considering both contributions on an equal footing is thus essential should one attempt to compare theoretical ZPR results with experimental data.},
Keywords = {IMCN/MODL},
language = {Anglais},
journal = {{Physical Review B}},
volume = {106},
number = {8},
pages = {085137},
issn = {2469-9969},
doi = {10.1103/physrevb.106.085137},
publisher = {American Physical Society (APS)},
year = {2022},
url = {http://hdl.handle.net/2078.1/269464}}

V. Vasilchenko, A. Zhugayevych, and X. Gonze, « Variational polaron equations applied to the anisotropic Fröhlich model, » Physical Review B, vol. 105, iss. 21, p. 214301, 2022.
[Bibtex]

@article{vasilchenko2022,
title = {{Variational polaron equations applied to the anisotropic Fr{\"o}hlich model}},
author = {Vasilchenko, Vasilii and Zhugayevych, Andriy and Gonze, Xavier},
Keywords = {IMCN/MODL},
language = {Anglais},
journal = {{Physical Review B}},
volume = {105},
number = {21},
pages = {214301},
issn = {2469-9969},
doi = {10.1103/physrevb.105.214301},
publisher = {American Physical Society (APS)},
year = {2022},
url = {http://hdl.handle.net/2078.1/269454}}

D. V. Semenok, W. Chen, X. Huang, D. Zhou, I. A. Kruglov, A. B. Mazitov, M. Galasso, C. Tantardini, X. Gonze, A. G. Kvashnin, A. R. Oganov, and T. Cui, « Sr-Doped Superionic Hydrogen Glass: Synthesis and Properties of SrH22, » Advanced Materials, vol. 34, iss. 27, p. 2200924, 2022.
[Bibtex]

@article{semenok2022,
title = {{Sr-Doped Superionic Hydrogen Glass: Synthesis and Properties of SrH22}},
author = {Semenok, Dmitrii V. and Chen, Wuhao and Huang, Xiaoli and Zhou, Di and Kruglov, Ivan A. and Mazitov, Arslan B. and Galasso, Michele and Tantardini, Christian and Gonze, Xavier and Kvashnin, Alexander G. and Oganov, Artem R. and Cui, Tian},
abstract = {Recently, several research groups announced reaching the point of metallization of hydrogen above 400 GPa. Despite notable progress, detecting superconductivity in compressed hydrogen remains an unsolved problem. Following the mainstream of extensive investigations of compressed metal polyhydrides, here small doping of molecular hydrogen by strontium is demonstrated to lead to a dramatic reduction in the metallization pressure to �200 GPa. Studying the high-pressure chemistry of the Sr�H system, the formation of several new phases is observed: C2/m-Sr3H13, pseudocubic SrH6, SrH9 with cubic F43m-Sr sublattice, and pseudo tetragonal superionic P1-SrH22, the metal hydride with the highest hydrogen content (96 at%) discovered so far. High diffusion coefficients of hydrogen in the latter phase DH = 0.2�2.1 � 10-9 m2 s-1 indicate an amorphous state of the H-sublattice, whereas the strontium sublattice remains solid. Unlike Ca and Y, strontium forms molecular semiconducting polyhydrides, whereas calcium and yttrium polyhydrides are high-TC superconductors with an atomic H sublattice. The discovered SrH22, a kind of hydrogen sponge, opens a new class of materials with ultrahigh content of hydrogen.},
Keywords = {IMCN/MODL , Mechanical Engineering , Mechanics of Materials , General Materials Science},
language = {Anglais},
journal = {{Advanced Materials}},
volume = {34},
number = {27},
pages = {2200924},
issn = {1521-4095},
doi = {10.1002/adma.202200924},
publisher = {Wiley},
year = {2022},
url = {http://hdl.handle.net/2078.1/269472}}

X. Gonze, B. Seddon, J. A. Elliott, C. Tantardini, and A. V. Shapeev, « Constrained Density Functional Theory: A Potential-Based Self-Consistency Approach, » Journal of Chemical Theory and Computation, vol. 18, iss. 10, pp. 6099-6110, 2022.
[Bibtex]

@article{gonze2022,
title = {{Constrained Density Functional Theory: A Potential-Based Self-Consistency Approach}},
author = {Gonze, Xavier and Seddon, Benjamin and Elliott, James A. and Tantardini, Christian and Shapeev, Alexander V.},
abstract = {Chemical reactions, charge transfer reactions, and magnetic materials are notoriously difficult to describe within Kohn�Sham density functional theory, which is strictly a ground-state technique. However, over the last few decades, an approximate method known as constrained density functional theory (cDFT) has been developed to model low-lying excitations linked to charge transfer or spin fluctuations. Nevertheless, despite becoming very popular due to its versatility, low computational cost, and availability in numerous software applications, none of the previous cDFT implementations is strictly similar to the corresponding ground-state self-consistent density functional theory: the target value of constraints (e.g., local magnetization) is not treated equivalently with atomic positions or lattice parameters. In the present work, by considering a potential-based formulation of the self-consistency problem, the cDFT is recast in the same framework as Kohn�Sham DFT: a new functional of the potential that includes the constraints is proposed, where the constraints, the atomic positions, or the lattice parameters are treated all alike, while all other ingredients of the usual potential-based DFT algorithms are unchanged, thanks to the formulation of the adequate residual. Tests of this approach for the case of spin constraints (collinear and noncollinear) and charge constraints are performed. Expressions for the derivatives with respect to constraints (e.g., the spin torque) for the atomic forces and the stress tensor in cDFT are provided. The latter allows one to study striction effects as a function of the angle between spins. We apply this formalism to body-centered cubic iron and first reproduce the well-known magnetization amplitude as a function of the angle between local magnetizations. We also study stress as a function of such an angle. Then, the local collinear magnetization and the local atomic charge are varied together. Since the atomic spin magnetizations, local atomic charges, atomic positions, and lattice parameters are treated on an equal footing, this formalism is an ideal starting point for the generation of model Hamiltonians and machine-learning potentials, computation of second or third derivatives of the energy as delivered from density-functional perturbation theory, or for second-principles approaches.},
Keywords = {IMCN/MODL , Physical and Theoretical Chemistry , Computer Science Applications},
language = {Anglais},
journal = {{Journal of Chemical Theory and Computation}},
volume = {18},
number = {10},
pages = {6099-6110},
issn = {1549-9626},
doi = {10.1021/acs.jctc.2c00673},
publisher = {American Chemical Society (ACS)},
year = {2022},
url = {http://hdl.handle.net/2078.1/269471}}

J. C. de Abreu, J. P. Nery, M. Giantomassi, X. Gonze, and M. J. Verstraete, « Spectroscopic signatures of nonpolarons: the case of diamond, » Physical Chemistry Chemical Physics, vol. 24, iss. 20, pp. 12580-12591, 2022.
[Bibtex]

@article{abreu2022,
title = {{Spectroscopic signatures of nonpolarons: the case of diamond}},
author = {de Abreu, Joao C. and Nery, Jean Paul and Giantomassi, Matteo and Gonze, Xavier and Verstraete, Matthieu J.},
abstract = {Polarons are quasi-particles made from electrons interacting with vibrations in crystal lattices. They derive their name from the strong electron-vibration polar interactions in ionic systems, that induce spectroscopic and optical signatures of such quasi-particles. In this paper, we focus on diamond, a nonpolar crystal with inversion symmetry which nevertheless shows interesting signatures stemming from electron-vibration interactions, better denoted ��nonpolaron�� signatures in this case. The (non)polaronic effects are produced by short-range crystal fields, while long-range quadrupoles only have a small influence. The corresponding many-body spectral function has a characteristic energy dependence, showing a plateau structure that is similar to but distinct from the satellites observed in the polar Fro�hlich case. We determine the temperature-dependent spectral function of diamond by two methods: the standard Dyson�Migdal approach, which calculates electron�phonon interactions within the lowestorder expansion of the self-energy, and the cumulant expansion, which includes higher orders of electron�phonon interactions. The latter corrects the nonpolaron energies and broadening, providing a more realistic spectral function, which we examine in detail for both conduction and valence band edges.},
Keywords = {IMCN/MODL , CISM:CECI , Physical and Theoretical Chemistry , General Physics and Astronomy},
language = {Anglais},
journal = {{Physical Chemistry Chemical Physics}},
volume = {24},
number = {20},
pages = {12580-12591},
issn = {1463-9084},
doi = {10.1039/d2cp01012g},
publisher = {{Royal Society of Chemistry (RSC)}},
year = {2022},
url = {http://hdl.handle.net/2078.1/267976}}

S. P. Ramkumar, G. Petretto, W. Chen, H. Pereira Coutada Miranda, X. Gonze, and G. Rignanese, « First-principles investigation of czts raman spectra, » Physical review materials, vol. 6, iss. 3, p. 35403, 2022.
[Bibtex]

@article{ramkumar2022,
title = {First-principles investigation of CZTS Raman spectra},
author = {Ramkumar, S.P. and Petretto, Guido and Chen, Wei and Pereira Coutada Miranda, Henrique and Gonze, Xavier and Rignanese, Gian-Marco},
abstract = {Cu2ZnSnS4 (CZTS) is an earth-abundant photovoltaic absorber material predicted to provide a sustainable solution for commercial solar applications. However, the efficiency of such solar cells is rather limited, cation disorder being often designated as the culprit. Raman spectroscopy has been widely used to characterize CZTS. Nonetheless, the interpretation of the spectra in terms of the atomic-scale disorder is precluded by the lack of consensus between theoretical and experimental results. In particular, there is a strong discrepancy in the relative intensities of the two prominent A phonon peaks of the spectra. In the present study, we demonstrate that the internal parameters characterizing the position of the S atoms strongly influence these intensities. We show that agreement with experiments can be completely recovered when adopting the geometry computed using a hybrid exchange-correlation functional. Finally, using special quasirandom structures, we demonstrate that the disorder only leads to a change of the shape of the Raman peaks (tailing or leading edges, shouldering and splitting). This could be exploited to assess the quality of the sample in terms of how ordered they are.},
Keywords = {IMCN/MODL , CISM:CECI , Physics and Astronomy (miscellaneous) , General Materials Science},
language = {Anglais},
journal = {Physical Review Materials},
volume = {6},
number = {3},
pages = {035403},
issn = {2475-9953},
doi = {10.1103/physrevmaterials.6.035403},
publisher = {American Physical Society (APS)},
year = {2022},
url = {http://hdl.handle.net/2078.1/259689}}

2021

I. Guster, P. Melo, B. A. A. Martin, V. Brousseau-Couture, J. C. de Abreu, A. Miglio, M. Giantomassi, M. Côté, J. M. Frost, M. J. Verstraete, and X. Gonze, « Fröhlich polaron effective mass and localization length in cubic materials: Degenerate and anisotropic electronic bands, » Physical Review B, vol. 104, iss. 23, p. 235123, 2021.
[Bibtex]

@article{guster2021,
title = {{Fr{\"o}hlich polaron effective mass and localization length in cubic materials: Degenerate and anisotropic electronic bands}},
author = {Guster, Ionel-Bogdan and Melo, Pedro and Martin, Bradley A. A. and Brousseau-Couture, V�ronique and de Abreu, Joao C. and Miglio, Anna and Giantomassi, Matteo and Côté, Michel and Frost, Jarvist M. and Verstraete, Matthieu J. and Gonze, Xavier},
abstract = {Polarons, that is, charge carriers correlated with lattice deformations, are ubiquitous quasiparticles in semiconductors, and play an important role in electrical conductivity. To date most theoretical studies of so-called large polarons, in which the lattice can be considered as a continuum, have focused on the original Fr�hlich model: a simple (nondegenerate) parabolic isotropic electronic band coupled to one dispersionless longitudinal optical phonon branch. The Fr�hlich model allows one to understand characteristics such as polaron formation energy, radius, effective mass, and mobility. Real cubic materials, instead, have electronic band extrema that are often degenerate (e.g., threefold degeneracy of the valence band), or anisotropic (e.g., conduction bands at X or L), and present several phonon modes. In the present paper, we address such issues. We keep the continuum hypothesis inherent to the large polaron Fr�hlich model, but waive the isotropic and nondegeneracy hypotheses, and also include multiple phonon branches. For polaron effective masses, working at the lowest order of perturbation theory, we provide analytical results for the case of anisotropic electronic energy dispersion, with two distinct effective masses (uniaxial) and numerical simulations for the degenerate three-band case, typical of III-V and II-VI semiconductor valence bands. We also deal with the strong-coupling limit, using a variational treatment: we propose trial wave functions for the above-mentioned cases, providing polaron radii and energies. Then, we evaluate the polaron formation energies, effective masses, and localization lengths using parameters representative of a dozen II-VI, III-V, and oxide semiconductors, for both electron and hole polarons. We show that for some cases perturbation theory (the weak-coupling approach) breaks down. In some other cases, the strong-coupling approach reveals that the large polaron hypothesis is not valid, which is another distinct breakdown. In the nondegenerate case, we compare the perturbative approach with the Feynman path integral approach in characterizing polarons in the weak-coupling limit. Thus, based on theoretical results for cubic materials, the present paper characterizes the validity of the continuum hypothesis for a large set of 20 materials.},
Keywords = {IMCN/MODL , CISM:CECI},
language = {Anglais},
journal = {{Physical Review B}},
volume = {104},
number = {23},
pages = {235123},
issn = {2469-9969},
doi = {10.1103/physrevb.104.235123},
publisher = {American Physical Society (APS)},
year = {2021},
url = {http://hdl.handle.net/2078.1/257908}}

J. Bouquiaux, S. Poncé, Y. Jia, A. Miglio, M. Mikami, and X. Gonze, « Importance of Long-Range Channel Sr Displacements for the Narrow Emission in Sr[Li2Al2O2N2]:Eu2+Phosphor, » Advanced Optical Materials, p. 2100649, 2021.
[Bibtex]

@article{bouquiaux2021,
title = {{Importance of Long-Range Channel Sr Displacements for the Narrow Emission in Sr[Li2Al2O2N2]:Eu2+Phosphor}},
author = {Bouquiaux, Julien and Ponc\'e, Samuel and Jia, Yongchao and Miglio, Anna and Mikami, Masayoshi and Gonze, Xavier},
abstract = {The recently discovered Sr[Li2Al2O2N2]:Eu2+ red phosphor, candidate for the next generation of eco-efficient white light-emitting diodes, exhibits excellent emission spectral position and exceptionally small linewidth. It belongs to the UCr4C4-structure family of phosphors containing many potential candidates for commercial phosphors, whose small linewidth, tentatively ascribed to the high-symmetry cuboid environment of the doping site, has drawn the attention of researchers in the last five years. Density functional theory, ?SCF method, and configuration coordinate models (CCM) are used to provide a complete characterization of this material. Using a multi-dimensional CCM, an accurate description of the coupling of the vibronic structure with the electronic 5d?4f transition is obtained, including the partial Huang�Rhys factors and frequency of the dominant modes. It is shown that, in addition to the first-coordination shell cuboid deformation mode, low-frequency phonon modes involving chains of strontium atoms along the tetragonal axis shape the emission linewidth in Sr[Li2Al2O2N2]:Eu2+. This finding sheds new light on the emission properties of UCr4C4-structure phosphors, possessing similar Ca/Sr/Ba channel. The approach provides a robust theoretical framework to systematically study the emission spectra of such Eu-doped phosphors, and predict candidates with expected similar or even sharper linewidth.},
Keywords = {IMCN/MODL , CISM:CECI , Atomic and Molecular Physics , and Optics , Electronic , Optical and Magnetic Materials},
language = {Anglais},
journal = {{Advanced Optical Materials}},
pages = {2100649},
issn = {2195-1071},
doi = {10.1002/adom.202100649},
publisher = {Wiley},
year = {2021},
url = {http://hdl.handle.net/2078.1/251075}}

C. Tantardini and X. Gonze, « Band gap bowing and spectral width of Ga(1-x)InxN alloys for modelling light emitting diodes, » Physica B: Condensed Matter, vol. 625, iss. -, p. 413481, 2021.
[Bibtex]

@article{tantardini2021a,
title = {{Band gap bowing and spectral width of Ga(1-x)InxN alloys for modelling light emitting diodes}},
author = {Tantardini, Christian and Gonze, Xavier},
abstract = {Ga(1-??)In??N alloys, widely employed to produce light-emitting diodes, exhibit a bowing of the band gap as a function of concentration ??, and a luminescence spectral width which differs from the expected value of 1.8 kT. Through first-principles calculations, based on many-body perturbation theory and density-functional theory with a meta-GGA exchange�correlation functional, we explore jointly these effects, in an exhaustive set of Ga(1-??)In??N supercells with 16 atoms. We disentangle the bowing due to the average volume change with the one due local atomic configuration and local relaxation. The first one account for about 40% of the bowing, despite that fact that the change of volume with respect to concentration is nearly linear (Vegard�s law). The computed bowing parameter is 1.39 eV. The experimental broadening between 3 kT and 8 kT, not examined theoretically until now, is well accounted by local atomic configuration changes and lifting of the degeneracy of the top of the valence band.},
Keywords = {IMCN/MODL , Electrical and Electronic Engineering , Condensed Matter Physics , Electronic , Optical and Magnetic Materials},
language = {Anglais},
journal = {{Physica B: Condensed Matter}},
volume = {625},
number = {-},
pages = {413481},
issn = {0921-4526},
doi = {10.1016/j.physb.2021.413481},
publisher = {Elsevier BV},
year = {2021},
url = {http://hdl.handle.net/2078.1/254289}}

C. Tantardini, A. G. Kvashnin, C. Gatti, B. I. Yakobson, and X. Gonze, « Computational Modeling of 2D Materials under High Pressure and Their Chemical Bonding: Silicene as Possible Field-Effect Transistor, » ACS Nano, vol. 15, iss. 4, pp. 6861-6871, 2021.
[Bibtex]

@article{tantardini2021,
title = {{Computational Modeling of 2D Materials under High Pressure and Their Chemical Bonding: Silicene as Possible Field-Effect Transistor}},
author = {Tantardini, Christian and Kvashnin, Alexander G. and Gatti, Carlo and Yakobson, Boris I. and Gonze, Xavier},
abstract = {To study the possibility for silicene to be employed as a field-effect transistor (FET) pressure sensor, we explore the chemistry of monolayer and multilayered silicene focusing on the change in hybridization under pressure. Ab initio computations show that the effect of pressure depends greatly on the thickness of the silicene film, but also reveals the influence of real experimental conditions, where the pressure is not hydrostatic. For this purpose, we introduce anisotropic strain states. With pure uniaxial stress applied to silicene layers, a path for sp3 silicon to sp3d silicon is found, unlike with pure hydrostatic pressure. Even with mixed-mode stress (in-plane pressure half of the out-of-plane one), we find no such path. In addition to introducing our theoretical approach to study 2D materials, we show how the hybridization change of silicene under pressure makes it a good FET pressure sensor.},
Keywords = {IMCN/MODL , General Engineering , General Physics and Astronomy , General Materials Science},
language = {Anglais},
journal = {{ACS Nano}},
volume = {15},
number = {4},
pages = {6861-6871},
issn = {1936-086X},
doi = {10.1021/acsnano.0c10609},
publisher = {American Chemical Society (ACS)},
year = {2021},
url = {http://hdl.handle.net/2078.1/245695}}

2020

F. Brown-Altvater, G. Antonius, T. Rangel, M. Giantomassi, C. Draxl, X. Gonze, S. G. Louie, and J. B. Neaton, « Band gap renormalization, carrier mobilities, and the electron-phonon self-energy in crystalline naphthalene, » Physical Review B, vol. 101, iss. 16, p. 165102, 2020.
[Bibtex]

@article{brown2020,
title = {{Band gap renormalization, carrier mobilities, and the electron-phonon self-energy in crystalline naphthalene}},
author = {Brown-Altvater, Florian and Antonius, Gabriel and Rangel, Tonatiuh and Giantomassi, Matteo and Draxl, Claudia and Gonze, Xavier and Louie, Steven G. and Neaton, Jeffrey B.},
abstract = {Organic molecular crystals are expected to feature appreciable electron-phonon interactions that influence their electronic properties at zero and finite temperature. In this work, we report first-principles calculations and an analysis of the electron-phonon self-energy in naphthalene crystals. We compute the zero-point renormalization and temperature dependence of the fundamental band gap, and the resulting scattering lifetimes of electronic states near the valence- and conduction-band edges employing density functional theory. Further, our calculated phonon renormalization of the GW-corrected quasiparticle band structure predicts a fundamental band gap of 5 eV for naphthalene at room temperature, in good agreement with experiments. From our calculated phonon-induced electron lifetimes, we obtain the temperature-dependent mobilities of electrons and holes in good agreement with experimental measurements at room temperature. Finally, we show that an approximate energy self-consistent computational scheme for the electron-phonon self-energy leads to the prediction of strong satellite bands in the electronic band structure. We find that a single calculation of the self-energy can reproduce the self-consistent results of the band gap renormalization and electrical mobilities for naphthalene, provided that the on-the-mass-shell approximation is used, i.e., if the self-energy is evaluated at the bare eigenvalues.},
Keywords = {IMCN/MODL},
language = {Anglais},
journal = {{Physical Review B}},
volume = {101},
number = {16},
pages = {165102},
issn = {2469-9969},
doi = {10.1103/physrevb.101.165102},
publisher = {American Physical Society (APS)},
year = {2020},
url = {http://hdl.handle.net/2078.1/252027}}

Y. Jia, S. Poncé, A. Miglio, M. Mikami, and X. Gonze, « Design rule for the emission linewidth of Eu2+-activated phosphors, » Journal of Luminescence, vol. 224, p. 117258, 2020.
[Bibtex]

@article{jia2020,
title = {{Design rule for the emission linewidth of Eu2+-activated phosphors}},
author = {Jia, Yongchao and Ponc\'e, Samuel and Miglio, Anna and Mikami, Masayoshi and Gonze, Xavier},
abstract = {We study from first principles the emission linewidth of Eu2+-doped LED phosphors. Based on the one-dimensional configuration coordinate model, an analysis of first principles data obtained for fifteen compounds show that, at working temperature, the linewidth of Eu2+ emission band in solids is negligibly affected by quantum effects, and can be extracted from the Franck�Condon energy shifts. For a fixed Stokes shift, the difference of Franck�Condon energy shifts in the excited and ground states is the key factor for the FWHM determination. Narrow emission Eu2+-doped LED phosphors are expected for the case with large positive value of such difference.},
Keywords = {IMCN/MODL , CISM:CECI , Condensed Matter Physics , Biochemistry , General Chemistry , Atomic and Molecular Physics , and Optics , Biophysics},
language = {Anglais},
journal = {{Journal of Luminescence}},
volume = {224},
pages = {117258},
issn = {0022-2313},
doi = {10.1016/j.jlumin.2020.117258},
publisher = {Elsevier BV},
year = {2020},
url = {http://hdl.handle.net/2078.1/250672}}

B. Van Troeye, A. Lherbier, S. M-M. Dubois, J. Charlier, and X. Gonze, « First-principles prediction of lattice coherency in van der Waals heterostructures, » arXiv, 2020.
[Bibtex]

@article{vantroeye2020,
title = {{First-principles prediction of lattice coherency in van der Waals heterostructures}},
author = {Van Troeye, Benoit and Lherbier, Aur�lien and Dubois, Simon M-M and Charlier, Jean-Christophe and Gonze, Xavier},
abstract = {The emergence of superconductivity in slightly-misaligned graphene bilayer [1] and moir� excitons in MoSe2-WSe2 van der Waals (vdW) heterostructures [2] is intimately related to the formation of a 2D superlattice in those systems. At variance, perfect primitive lattice matching of the constituent layers has also been reported in some vdW-heterostructures [3-5], highlighting the richness of interfaces in the 2D world. In this work, the determination of the nature of such interface, from first principles, is demonstrated. To do so, an extension of the Frenkel-Kontorova (FK) model [6] is presented, linked to first principles calculations, and used to predict lattice coherency for a set of 56 vdW-heterostructures. Computational predictions agree with experiments, when available. New superlattices as well as perfectly-matching interfaces are predicted.},
Keywords = {IMCN/MODL , CISM:CECI},
language = {Anglais},
journal = {{arXiv}},
year = {2020},
url = {http://hdl.handle.net/2078.1/237674}}

A. Miglio, V. Brousseau-Couture, E. Godbout, G. Antonius, Y. Chan, S. G. Louie, M. Côté, M. Giantomassi, and X. Gonze, « Predominance of non-adiabatic effects in zero-point renormalization of the electronic band gap, » npj Computational Materials, vol. 6, iss. 1, p. 167, 2020.
[Bibtex]

@article{miglio2020,
title = {{Predominance of non-adiabatic effects in zero-point renormalization of the electronic band gap}},
author = {Miglio, Anna and Brousseau-Couture, V�ronique and Godbout, Emile and Antonius, Gabriel and Chan, Yang-Hao and Louie, Steven G. and Côté, Michel and Giantomassi, Matteo and Gonze, Xavier},
abstract = {Electronic and optical properties of materials are affected by atomic motion through the electron-phonon interaction: not only band gaps change with temperature, but even at absolute zero temperature, zero-point motion causes band-gap renormalization. We present the first large-scale first-principles evaluation of the zero-point renormalization of band edges beyond the adiabatic approximation. For materials with light elements, the band gap renormalization is often larger than 0.3 eV, and up to 0.7 eV. This effect cannot be ignored if accurate band gaps are sought. For infrared-active materials, global agreement with available experimental data is obtained only when non-adiabatic effects are taken into account. They even dominate zero-point renormalization for many materials, as shown by a generalized Fr�hlich model that includes multiple phonon branches, anisotropic and degenerate electronic extrema, whose range of validity is established by comparison with first-principles results.},
Keywords = {IMCN/MODL , CISM:CECI},
language = {Anglais},
journal = {{npj Computational Materials}},
volume = {6},
number = {1},
pages = {167},
issn = {2057-3960},
doi = {10.1038/s41524-020-00434-z},
publisher = {Springer Science and Business Media LLC},
year = {2020},
url = {http://hdl.handle.net/2078.1/237683}}

G. Brunin, H. Pereira Coutada Miranda, M. Giantomassi, M. Royo, M. Stengel, M. J. Verstraete, X. Gonze, G. Rignanese, and G. Hautier, « Electron-Phonon beyond Fröhlich: Dynamical Quadrupoles in Polar and Covalent Solids, » Physical Review Letters, vol. 125, iss. 13, p. 136601, 2020.
[Bibtex]

@article{brunin2020,
title = {{Electron-Phonon beyond Fröhlich: Dynamical Quadrupoles in Polar and Covalent Solids}},
author = {Brunin, Guillaume and Pereira Coutada Miranda, Henrique and Giantomassi, Matteo and Royo, Miquel and Stengel, Massimiliano and Verstraete, Matthieu J. and Gonze, Xavier and Rignanese, Gian-Marco and Hautier, Geoffroy},
abstract = {We include the treatment of quadrupolar fields beyond the Fröhlich interaction in the first-principles electron-phonon vertex in semiconductors. Such quadrupolar fields induce long-range interactions that have to be taken into account for accurate physical results.We apply our formalism to Si (nonpolar), GaAs, and GaP (polar) and demonstrate that electron mobilities show large errors if dynamical quadrupoles are not properly treated.},
Keywords = {IMCN/MODL , CISM:CECI , General Physics and Astronomy},
language = {Anglais},
journal = {{Physical Review Letters}},
volume = {125},
number = {13},
pages = {136601},
issn = {1079-7114},
doi = {10.1103/physrevlett.125.136601},
publisher = {{American Physical Society (APS)}},
year = {2020},
url = {http://hdl.handle.net/2078.1/235872}}

G. Brunin, H. Pereira Coutada Miranda, M. Giantomassi, M. Royo, M. Stengel, M. J. Verstraete, X. Gonze, G. Rignanese, and G. Hautier, « Phonon-limited electron mobility in Si, GaAs, and GaP with exact treatment of dynamical quadrupoles, » Physical Review B, vol. 102, iss. 9, p. 94308, 2020.
[Bibtex]

@article{brunin2020a,
title = {{Phonon-limited electron mobility in Si, GaAs, and GaP with exact treatment of dynamical quadrupoles}},
author = {Brunin, Guillaume and Pereira Coutada Miranda, Henrique and Giantomassi, Matteo and Royo, Miquel and Stengel, Massimiliano and Verstraete, Matthieu J. and Gonze, Xavier and Rignanese, Gian-Marco and Hautier, Geoffroy},
abstract = {We describe a new approach to compute the electron-phonon self-energy and carrier mobilities in semiconductors. Our implementation does not require a localized basis set to interpolate the electron-phonon matrix elements, with the advantage that computations can be easily automated. Scattering potentials are interpolated on dense q meshes using Fourier transforms and ab initio models to describe the long-range potentials generated by dipoles and quadrupoles. To reduce significantly the computational cost, we take advantage of crystal symmetries and employ the linear tetrahedron method and double-grid integration schemes,in conjunction with filtering techniques in the Brillouin zone. We report results for the electron mobility in Si,GaAs, and GaP obtained with this new methodology.},
Keywords = {IMNC/MODL , CISM:CECI},
language = {Anglais},
journal = {{Physical Review B}},
volume = {102},
number = {9},
pages = {094308},
issn = {2469-9969},
doi = {10.1103/physrevb.102.094308},
publisher = {{American Physical Society (APS)}},
year = {2020},
url = {http://hdl.handle.net/2078.1/235874}}

D. Waroquiers, J. George, M. Horton, S. Schenk, K. A. Persson, G. Rignanese, X. Gonze, and G. Hautier, « ChemEnv: a fast and robust coordination environment identification tool, » Acta Crystallographica Section B Structural Science, Crystal Engineering and Materials, vol. 76, iss. 4, pp. 683-695, 2020.
[Bibtex]

@article{waroquiers2020,
title = {{ChemEnv: a fast and robust coordination environment identification tool}},
author = {Waroquiers, David and George, Janine and Horton, Matthew and Schenk, Stephan and Persson, Kristin A. and Rignanese, Gian-Marco and Gonze, Xavier and Hautier, Geoffroy},
abstract = {Coordination or local environments have been used to describe, analyze and understand crystal structures for more than a century. Here, a new tool called ChemEnv, which can identify coordination environments in a fast and robust manner, is presented. In contrast to previous tools, the assessment of the coordination environments is not biased by small distortions of the crystal structure. Its robust and fast implementation enables the analysis of large databases of structures. The code is available open source within the pymatgen package and the software can also be used through a web app available on http://crystaltoolkit.org through the Materials Project.},
Keywords = {CISM:CECI , IMCN/MODL , Materials Chemistry , Atomic and Molecular Physics , and Optics , Electronic , Optical and Magnetic Materials , Metals and Alloys},
language = {Anglais},
journal = {{Acta Crystallographica Section B Structural Science, Crystal Engineering and Materials}},
volume = {76},
number = {4},
pages = {683-695},
issn = {2052-5206},
doi = {10.1107/s2052520620007994},
publisher = {International Union of Crystallography (IUCr)},
year = {2020},
url = {http://hdl.handle.net/2078.1/232058}}

V. Kumar, D. Di Stefano, G. Rignanese, and X. Gonze, « Li diffusion in Si and LiSi: Nuclear quantum effects and anharmonicity, » The Journal of Chemical Physics, vol. 152, iss. 24, p. 244101, 2020.
[Bibtex]

@article{kumar2020,
title = {{Li diffusion in Si and LiSi: Nuclear quantum effects and anharmonicity}},
author = {Kumar, Vishank and Di Stefano, Davide and Rignanese, Gian-Marco and Gonze, Xavier},
abstract = {The diffusion of Li in bulk Si and crystalline LiSi is investigated over a wide range of temperatures employing first-principles calculations based on density functional theory, transition state theory, and the kinetic Monte Carlo method. Nuclear quantum effects are incorporated by computing the vibrational spectrum and its effect on the effective energy barrier. The Li diffusion coefficient in bulk Si calculated with such quantum effects is ∼33% lower than the classical limit near room temperature due to higher effective energy barrier and tends to the classical limit at a high temperature (>1000 K). The presence of anharmonicity, estimated by the quasiharmonic approximation and the cBΩ model, increases the diffusion coefficient by ∼60%. For Li diffusion in LiSi with multiple vacancy jumps, we obtain an effective diffusion barrier of 0.27 eV ± 0.01 eV. In the Li–Si system, the quantum mechanical effects are only marginally significant at room temperature.},
Keywords = {CECI:CISM , IMCN/MODL , Physical and Theoretical Chemistry , General Physics and Astronomy},
language = {Anglais},
journal = {{The Journal of Chemical Physics}},
volume = {152},
number = {24},
pages = {244101},
issn = {1089-7690},
doi = {10.1063/5.0007648},
publisher = {AIP Publishing},
year = {2020},
url = {http://hdl.handle.net/2078.1/231672}}

A. H. Romero, D. C. Allan, B. Amadon, G. Antonius, T. Applencourt, L. Baguet, J. Bieder, F. Bottin, J. Bouchet, E. Bousquet, F. Bruneval, G. Brunin, D. Caliste, M. Côté, J. Denier, C. Dreyer, P. Ghosez, M. Giantomassi, Y. Gillet, O. Gingras, D. R. Hamann, G. Hautier, F. Jollet, G. Jomard, A. Martin, H. Pereira Coutada Miranda, F. Naccarato, G. Petretto, N. A. Pike, V. Planes, S. Prokhorenko, T. Rangel, F. Ricci, G. Rignanese, M. Royo, M. Stengel, M. Torrent, M. van Setten, B. Van Troeye, M. J. Verstraete, J. Wiktor, J. W. Zwanziger, and X. Gonze, « ABINIT: Overview and focus on selected capabilities, » The Journal of Chemical Physics, vol. 152, iss. 12, p. 124102, 2020.
[Bibtex]

@article{romero2020,
title = {{ABINIT: Overview and focus on selected capabilities}},
author = {Romero, Aldo H. and Allan, Douglas C. and Amadon, Bernard and Antonius, Gabriel and Applencourt, Thomas and Baguet, Lucas and Bieder, Jordan and Bottin, Fran�ois and Bouchet, Johann and Bousquet, Eric and Bruneval, Fabien and Brunin, Guillaume and Caliste, Damien and Côté, Michel and Denier, Jules and Dreyer, Cyrus and Ghosez, Philippe and Giantomassi, Matteo and Gillet, Yannick and Gingras, Olivier and Hamann, Donald R. and Hautier, Geoffroy and Jollet, Fran�ois and Jomard, G�rald and Martin, Alexandre and Pereira Coutada Miranda, Henrique and Francesco Naccarato and Petretto, Guido and Pike, Nicholas A. and Planes, Valentin and Prokhorenko, Sergei and Rangel, Tonatiuh and Ricci, Fabio and Rignanese, Gian-Marco and Royo, Miquel and Stengel, Massimiliano and Torrent, Marc and van Setten, Michiel and Van Troeye, Benoit and Verstraete, Matthieu J. and Wiktor, Julia and Zwanziger, Josef W. and Gonze, Xavier},
abstract = {Abinit is probably the first electronic-structure package to have been released under an open-source license about 20 years ago. It implements density functional theory, density-functional perturbation theory (DFPT), many-body perturbation theory (GW approximation and Bethe�Salpeter equation), and more specific or advanced formalisms, such as dynamical mean-field theory (DMFT) and the �temperature-dependent effective potential� approach for anharmonic effects. Relying on planewaves for the representation of wavefunctions, density, and other space-dependent quantities, with pseudopotentials or projector-augmented waves (PAWs), it is well suited for the study of periodic materials, although nanostructures and molecules can be treated with the supercell technique. The present article starts with a brief description of the project, a summary of the theories upon which abinit relies, and a list of the associated capabilities. It then focuses on selected capabilities that might not be present in the majority of electronic structure packages either among planewave codes or, in general, treatment of strongly correlated materials using DMFT; materials under finite electric fields; properties at nuclei (electric field gradient, M�ssbauer shifts, and orbital magnetization); positron annihilation; Raman intensities and electro-optic effect; and DFPT calculations of response to strain perturbation (elastic constants and piezoelectricity), spatial dispersion (flexoelectricity), electronic mobility, temperature dependence of the gap, and spin-magnetic-field perturbation. The abinit DFPT implementation is very general, including systems with van der Waals interaction or with noncollinear magnetism. Community projects are also described: generation of pseudopotential and PAW datasets, high-throughput calculations (databases of phonon band structure, second-harmonic generation, and GW computations of bandgaps), and the library libpaw. abinit has strong links with many other software projects that are briefly mentioned.},
Keywords = {IMCN/MODL , CISM:CECI , Physical and Theoretical Chemistry , General Physics and Astronomy},
language = {Anglais},
journal = {{The Journal of Chemical Physics}},
volume = {152},
number = {12},
pages = {124102},
issn = {1089-7690},
doi = {10.1063/1.5144261},
publisher = {AIP Publishing},
year = {2020},
url = {http://hdl.handle.net/2078.1/228535}}

X. Gonze, B. Amadon, G. Antonius, F. Arnardi, L. Baguet, J. Beuken, J. Bieder, F. Bottin, J. Bouchet, E. Bousquet, N. Brouwer, F. Bruneval, G. Brunin, T. Cavignac, J. Charraud, W. Chen, M. Côté, S. Cottenier, J. Denier, G. Geneste, P. Ghosez, M. Giantomassi, Y. Gillet, O. Gingras, D. R. Hamann, G. Hautier, X. He, N. Helbig, N. Holzwarth, Y. Jia, F. Jollet, W. Lafargue-Dit-Hauret, K. Lejaeghere, M. A. L. Marques, A. Martin, C. Martins, H. Pereira Coutada Miranda, F. Naccarato, K. Persson, G. Petretto, V. Planes, Y. Pouillon, S. Prokhorenko, F. Ricci, G. Rignanese, A. H. Romero, M. M. Schmitt, M. Torrent, M. van Setten, B. Van Troeye, M. J. Verstraete, G. Zérah, and J. W. Zwanziger, « The Abinit project: Impact, environment and recent developments, » Computer Physics Communications, vol. 248, p. 107042, 2020.
[Bibtex]

@article{gonze2020,
title = {{The Abinit project: Impact, environment and recent developments}},
author = {Gonze, Xavier and Amadon, Bernard and Antonius, Gabriel and Arnardi, Frédéric and Baguet, Lucas and Beuken, Jean-Michel and Bieder, Jordan and Bottin, François and Bouchet, Johann and Bousquet, Eric and Brouwer, Nils and Bruneval, Fabien and Brunin, Guillaume and Cavignac, Théo and Charraud, Jean-Baptiste and Chen, Wei and Côté, Michel and Cottenier, Stefaan and Denier, Jules and Geneste, Grégory and Ghosez, Philippe and Giantomassi, Matteo and Gillet, Yannick and Gingras, Olivier and Hamann, Donald R. and Hautier, Geoffroy and He, Xu and Helbig, Nicole and Holzwarth, Natalie and Jia, Yongchao and Jollet, François and Lafargue-Dit-Hauret, William and Lejaeghere, Kurt and Marques, Miguel A.L. and Martin, Alexandre and Martins, Cyril and Pereira Coutada Miranda, Henrique and Naccarato, Francesco and Persson, Kristin and Petretto, Guido and Planes, Valentin and Pouillon, Yann and Prokhorenko, Sergei and Ricci, Fabio and Rignanese, Gian-Marco and Romero, Aldo H. and Schmitt, Michael Marcus and Torrent, Marc and van Setten, Michiel and Van Troeye, Benoit and Verstraete, Matthieu J. and Zérah, Gilles and Zwanziger, Josef W.},
Keywords = {IMCN/MODL , CISM:CECI , Hardware and Architecture , General Physics and Astronomy},
language = {Anglais},
journal = {{Computer Physics Communications}},
volume = {248},
pages = {107042},
issn = {0010-4655},
doi = {10.1016/j.cpc.2019.107042},
publisher = {Elsevier BV},
year = {2020},
url = {http://hdl.handle.net/2078.1/225653}}

2019

Y. Jia, S. Poncé, A. Miglio, M. Mikami, and X. Gonze, « Beyond the one-dimensional configuration coordinate model of photoluminescence, » Phys. Rev. B, vol. 100, p. 155109, 2019.
[Bibtex]

@article{jia2019,
title = {Beyond the one-dimensional configuration coordinate model of photoluminescence},
author = {Jia, Yongchao and Ponc\'e, Samuel and Miglio, Anna and Mikami, Masayoshi and Gonze, Xavier},
journal = {{Phys. Rev. B}},
volume = {100},
issue = {15},
pages = {155109},
numpages = {11},
year = {2019},
month = {Oct},
publisher = {American Physical Society},
doi = {10.1103/PhysRevB.100.155109},
url = {https://link.aps.org/doi/10.1103/PhysRevB.100.155109}
}

N. A. Pike, A. Dewandre, B. Van Troeye, X. Gonze, and M. J. Verstraete, « Vibrational and dielectric properties of monolayer transition metal dichalcogenides, » Phys. Rev. Materials, vol. 3, p. 74009, 2019.
[Bibtex]

@article{pike2019,
title = {Vibrational and dielectric properties of monolayer transition metal dichalcogenides},
author = {Pike, Nicholas A. and Dewandre, Antoine and Van Troeye, Benoit and Gonze, Xavier and Verstraete, Matthieu J.},
journal = {{Phys. Rev. Materials}},
volume = {3},
issue = {7},
pages = {074009},
numpages = {11},
year = {2019},
month = {Jul},
publisher = {{American Physical Society}},
doi = {10.1103/PhysRevMaterials.3.074009},
url = {https://link.aps.org/doi/10.1103/PhysRevMaterials.3.074009}
}

2018

Y. Jia, A. Miglio, M. Mikami, and X. Gonze, « Ab initio study of luminescence in Ce-doped Lu2SiO5: The role of oxygen vacancies on emission color and thermal quenching behavior, » Physical Review Materials, vol. 2, iss. 12, p. 125202, 2018.
[Bibtex]

@article{jia2018,
title = {Ab initio study of luminescence in {Ce}-doped {Lu2SiO5}: {The} role of oxygen vacancies on emission color and thermal quenching behavior},
author = {Jia, Yongchao and Miglio, Anna and Mikami, Masayoshi and Gonze, Xavier},
language = {Anglais},
journal = {{Physical Review Materials}},
volume = {2},
number = {12},
pages = {125202},
issn = {2475-9953},
doi = {10.1103/physrevmaterials.2.125202},
publisher = {American Physical Society (APS)},
year = {2018},
url = {http://hdl.handle.net/2078.1/214076}}

Y. Jia, A. Miglio, X. Gonze, and M. Mikami, « Ab-initio study of oxygen vacancy stability in bulk and Cerium-doped lutetium oxyorthosilicate, » Journal of Luminescence, vol. 204, pp. 499-505, 2018.
[Bibtex]

@article{jia2018a,
title = {Ab-initio study of oxygen vacancy stability in bulk and {Cerium}-doped lutetium oxyorthosilicate},
author = {Jia, Yongchao and Miglio, Anna and Gonze, Xavier and Mikami, Masayoshi},
abstract = {We study from first principles the stability of neutral and charged oxygen vacancies in lutetium oxyorthosilicate, Lu2SiO5, as well as its possible modification due to the presence of Ce3+, as present in commercial scintillators. We show that the neutral oxygen vacancy with the lowest formation energy forms at the oxygen sites within the [SiO4] tetrahedra instead of the interstitial oxygen site bonded exclusively to lutetium atoms. The discrepancy with a previous study is attributed to the quality of the pseudopotential. Support for these results is found by performing a bonding analysis of the oxygen sites, as well as oxygen vacancy calculations in the iso-structural Y2SiO5 compound. In addition, we find that the incorporation of Ce3+ ion does not affect the stability of oxygen vacancies in Lu2SiO5.},
Keywords = {Scintillator , Oxygen vacancy , Luminescence , Ab-initio calculation},
language = {Anglais},
journal = {{Journal of Luminescence}},
volume = {204},
pages = {499-505},
issn = {0022-2313},
doi = {10.1016/j.jlumin.2018.08.039},
publisher = {Elsevier BV},
year = {2018},
url = {http://hdl.handle.net/2078.1/214071}}

G. Petretto, X. Gonze, G. Hautier, and G. Rignanese, « Convergence and pitfalls of density functional perturbation theory phonons calculations from a high-throughput perspective, » Computational Materials Science, vol. 144, pp. 331-337, 2018.
[Bibtex]

@article{petretto2018,
title = {Convergence and pitfalls of density functional perturbation theory phonons calculations from a high-throughput perspective},
author = {Petretto, Guido and Gonze, Xavier and Hautier, Geoffroy and Rignanese, Gian-Marco},
abstract = {The diffusion of large databases collecting different kind of material properties from high-throughput density functional theory calculations has opened new paths in the study of materials science thanks to data mining and machine learning techniques. Phonon calculations have already been employed successfully to predict materials properties and interpret experimental data, e.g. phase stability, ferroelectricity and Raman spectra, so their availability for a large set of materials will further increase the analytical and redictive power at hand. Moving to a larger scale with density functional perturbation calculations, however, requires the presence of a robust framework to handle this challenging task. In light of this, we automatized the phonon calculation and applied the result to the analysis of the convergence trends for several materials. This allowed to identify and tackle some common problems emerging in this kind of simulations and to lay out the basis to obtain reliable phonon band structures from highthroughput calculations, as well as optimizing the approach to standard phonon simulations.},
Keywords = {IMCN/NAPS , CISM:CECI , General Physics and Astronomy , General Materials Science , General Computer Science , Mechanics of Materials , General Chemistry , Computational Mathematics , IMCN/NAPS , CISM:CECI},
language = {Anglais},
journal = {{Computational Materials Science}},
volume = {144},
pages = {331-337},
issn = {0927-0256},
doi = {10.1016/j.commatsci.2017.12.040},
publisher = {Elsevier BV},
year = {2018},
url = {http://hdl.handle.net/2078.1/191940}}

G. Petretto, S. Dwaraknath, H. Pereira Coutada Miranda, D. Winston, M. Giantomassi, M. van Setten, X. Gonze, K. A. Persson, G. Hautier, and G. Rignanese, « High-throughput density-functional perturbation theory phonons for inorganic materials, » Scientific Data, vol. 5, p. 180065, 2018.
[Bibtex]

@article{petretto2018a,
title = {High-throughput density-functional perturbation theory phonons for inorganic materials},
author = {Petretto, Guido and Dwaraknath, Shyam and Pereira Coutada Miranda, Henrique and Winston, Donald and Giantomassi, Matteo and van Setten, Michiel and Gonze, Xavier and Persson, Kristin A. and Hautier, Geoffroy and Rignanese, Gian-Marco},
abstract = {The knowledge of the vibrational properties of a material is of key importance to understand physical phenomena such as thermal conductivity, superconductivity, and ferroelectricity among others. However, detailed experimental phonon spectra are available only for a limited number of materials, which hinders the large-scale analysis of vibrational properties and their derived quantities. In this work, we perform ab initio calculations of the full phonon dispersion and vibrational density of states for 1521 semiconductor compounds in the harmonic approximation based on density functional perturbation theory. The data is collected along with derived dielectric and thermodynamic properties. We present the procedure used to obtain the results, the details of the provided database and a validation based on the comparison with experimental data.},
Keywords = {Statistics , Probability and Uncertainty , Statistics and Probability , Education , Library and Information Sciences , Information Systems , Computer Science Applications , IMCN/NAPS},
language = {Anglais},
journal = {{Scientific Data}},
volume = {5},
pages = {180065},
issn = {2052-4463},
doi = {10.1038/sdata.2018.65},
publisher = {Springer Nature},
year = {2018},
url = {http://hdl.handle.net/2078.1/197466}}

M. Wuttig, V. L. Deringer, X. Gonze, C. Bichara, and J. Raty, « Incipient Metals: Functional Materials with a Unique Bonding Mechanism, » Advanced Materials, vol. 30, iss. 51, p. 1803777, 2018.
[Bibtex]

@article{wuttig2018,
title = {{Incipient Metals: Functional Materials with a Unique Bonding Mechanism}},
author = {Wuttig, Matthias and Deringer, Volker L. and Gonze, Xavier and Bichara, Christophe and Raty, Jean-Yves},
abstract = {While solid-state materials are commonly classified as covalent, ionic, or metallic, there are cases that defy these iconic bonding mechanisms. Phasechange materials (PCMs) for data storage are a prominent example: they have been claimed to show �resonant bonding,� but a clear definition of this mechanism has been lacking. Here, it is shown that these solids are fundamentally different from resonant bonding in the ?-orbital systems of benzene and graphene, based on first-principles data for vibrational, optical, and polarizability properties. It is shown that PCMs and related materials exhibit a unique mechanism between covalent and metallic bonding. It is suggested that these materials be called �incipient metals,� and their bonding nature �metavalent�. Data for a diverse set of 58 materials show that metavalent bonding is not just a superposition of covalent and metallic cases, but instead gives rise to a unique and anomalous set of physical properties. This allows the derivation of a characteristic fingerprint of metavalent bonding, composed of five individual components and firmly rooted in physical properties. These findings are expected to accelerate the discovery and design of functional materials with attractive properties and applications, including nonvolatile memories, thermoelectrics, photonics, and quantum materials.},
Keywords = {Mechanical Engineering , General Materials Science , Mechanics of Materials},
language = {Anglais},
journal = {{Advanced Materials}},
volume = {30},
number = {51},
pages = {1803777},
issn = {0935-9648},
doi = {10.1002/adma.201803777},
publisher = {Wiley},
year = {2018},
url = {http://hdl.handle.net/2078.1/214078}}

G. Sandu, M. Coulombier, V. Kumar, H. G. Kassa, I. Avram, R. Ye, A. Stopin, D. Bonifazi, J. Gohy, P. Leclère, X. Gonze, T. Pardoen, A. Vlad, and S. Melinte, « Kinked silicon nanowires-enabled interweaving electrode configuration for lithium-ion batteries, » Scientific Reports, vol. 8, p. 9794, 2018.
[Bibtex]

@article{sandu2018,
title = {{Kinked silicon nanowires-enabled interweaving electrode configuration for lithium-ion batteries}},
author = {Sandu, Georgiana and Coulombier, Micha�l and Kumar, Vishank and Kassa, Hailu G. and Avram, Ionel and Ye, Ran and Stopin, Antoine and Bonifazi, Davide and Gohy, Jean-Fran�ois and Lecl\`ere, Philippe and Gonze, Xavier and Pardoen, Thomas and Vlad, Alexandru and Melinte, Sorin},
abstract = {A tri-dimensional interweaving kinked silicon nanowires (k-SiNWs) assembly, with a Ni current collector co-integrated, is evaluated as electrode configuration for lithium ion batteries. The large-scale fabrication of k-SiNWs is based on a procedure for continuous metal assisted chemical etching of Si, supported by a chemical peeling step that enables the reuse of the Si substrate. The kinks are triggered by a simple, repetitive etch-quench sequence in a HF and H2O2-based etchant. We find that the interlocking frameworks of k-SiNWs and multi-walled carbon nanotubes exhibit beneficial mechanical properties with a foam-like behavior amplified by the kinks and a suitable porosity for a minimal electrode deformation upon Li insertion. In addition, ionic liquid electrolyte systems associated with the integrated Ni current collector repress the detrimental effects related to the Si-Li alloying reaction, enabling high cycling stability with 80% capacity retention (1695 mAh/gSi) after 100 cycles. Areal capacities of 2.42 mAh/cm2 (1276 mAh/gelectrode) can be achieved at the maximum evaluated thickness (corresponding to 1.3 mgSi/cm2). This work emphasizes the versatility of the metal assisted chemical etching for the synthesis of advanced Si nanostructures for high performance lithium ion battery electrodes.},
Keywords = {ICTEAM:NANO},
language = {Anglais},
journal = {{Scientific Reports}},
volume = {8},
pages = {9794},
issn = {2045-2322},
doi = {10.1038/s41598-018-28108-3},
publisher = {Nature Publishing Group},
year = {2018},
url = {http://hdl.handle.net/2078.1/200156}}

B. Van Troeye, A. Lherbier, J. Charlier, and X. Gonze, « Large phosphorene in-plane contraction induced by interlayer interactions in graphene-phosphorene heterostructures, » Physical Review Materials, vol. 2, iss. 7, p. 74001, 2018.
[Bibtex]

@article{vantroeye2018,
title = {Large phosphorene in-plane contraction induced by interlayer interactions in graphene-phosphorene heterostructures},
author = {Van Troeye, Beno�t and Lherbier, Aur�lien and Charlier, Jean-Christophe and Gonze, Xavier},
abstract = {Intralayer deformation in van der Waals (vdW) heterostructures is generally assumed to be negligible due to the weak nature of the interactions between the layers, especially when the interfaces are found incoherent. In the present work, graphene-phosphorene vdW heterostructures are investigated with the density functional theory (DFT). The challenge of treating a nearly incommensurate (very large) supercell inDFT is bypassed by considering different energetic quantities in the grand canonical ensemble, alternative to the formation energy, in order to take into account the mismatch elastic contribution of the different layers. In the investigated heterostructures, it is found that phosphorene contracts by?4% in the armchair directionwhen compared to its free-standing form. This large contraction leads to important changes in terms of electronic properties, with the direct electronic optical transition of phosphorene becoming indirect in specific vdW eterostructures. More generally, such a contraction indicates strong substrate effects in supported or encapsulated phosphorene�neglected hitherto�and paves the way to substrate-controlled stresstronic in such 2D crystal. In addition, the stability of these vdW heterostructures is investigated as a function of the rotation angle between the layers and as a function of the stacking composition. The alignment of the specific crystalline directions of graphene and phosphorene is found energetically favored. In parallel, several models based onDFT-estimated quantities are presented; they allownotably a better understanding of the global mutual accommodation of 2D materials in their corresponding interfaces, that is predicted to be non-negligible even in the case of incommensurate interfaces.},
Keywords = {IMCN/NAPS , CISM:CECI},
language = {Anglais},
journal = {{Physical Review Materials}},
volume = {2},
number = {7},
pages = {074001},
issn = {2475-9953},
doi = {10.1103/physrevmaterials.2.074001},
publisher = {American Physical Society (APS)},
year = {2018},
url = {http://hdl.handle.net/2078.1/201078}}

A. Lherbier, G. Vander Marcken, B. Van Troeye, A. R. Botello-Méndez, J. J. Adjizian, G. Hautier, X. Gonze, G. Rignanese, and J. Charlier, « Lithiation properties of sp2 carbon allotropes, » Physical Review Materials, vol. 2, iss. 8, p. 85408, 2018.
[Bibtex]

@article{lherbier2018,
title = {Lithiation properties of sp2 carbon allotropes},
author = {Lherbier, Aur�lien and Vander Marcken, Gil and Van Troeye, Beno�t and Botello-M\'endez, Andr�s Rafael and Adjizian, Jean Joseph and Hautier, Geoffroy and Gonze, Xavier and Rignanese, Gian-Marco and Charlier, Jean-Christophe},
abstract = {Increasing the storage capacity of lithium electrodes, without altering their cyclability, is one of the key challenges for modern ion-based batteries. For graphite-based anodes, the well-known capacity limit is ?370 mAh/g, which corresponds to a lithium composition of Li1C6. Lithium intercalation is accompanied by a volume expansion of ?10%. In the present work, accurate first-principles methods are used to investigate the performance of different bulk sp2 carbon allotropes as anodes in lithium-ion batteries. Compared to graphite, which is an alternated stack of graphene layers (Bernal stacking) exhibiting a perfect hexagonal tiling, the layers of the other stacked systems considered are constructed from various polygonal carbon rings, such as squares, pentagons, hexagons, heptagons, octagons, and dodecagons. These sp2 allotropes, which appear locally in defective graphene and grain boundaries, can exhibit a substantial increase in specific capacity with respect to graphite (up to a factor of two, i.e., Li2C6) with only a relatively small volume expansion (at most 25%). The mechanisms for this predicted increase in the number of lithium atoms that can be hosted in these still hypothetical carbon crystals are analyzed in detail, yielding global strategies for improving lithium capacity in sp2 carbon-based batteries. In addition, these results offer an insight on the local mechanism of Li incorporation in randomly defective graphite.},
Keywords = {IMCN/NAPS , CISM:CECI},
language = {Anglais},
journal = {{Physical Review Materials}},
volume = {2},
number = {8},
pages = {085408},
issn = {2475-9953},
doi = {10.1103/physrevmaterials.2.085408},
publisher = {American Physical Society (APS)},
year = {2018},
url = {http://hdl.handle.net/2078.1/203763}}

J. P. Nery, P. B. Allen, G. Antonius, L. Reining, A. Miglio, and X. Gonze, « Quasiparticles and phonon satellites in spectral functions of semiconductors and insulators: Cumulants applied to the full first-principles theory and the Frohlich polaron, » Physical review B, vol. 97, iss. 11, p. 115145, 2018.
[Bibtex]

@article{nery2018,
title = {{Quasiparticles and phonon satellites in spectral functions of semiconductors and insulators: Cumulants applied to the full first-principles theory and the Frohlich polaron}},
author = {Nery, Jean Paul and Allen, Philip B. and Antonius, Gabriel and Reining, Lucia and Miglio, Anna and Gonze, Xavier},
Keywords = {IMCN/NAPS , CISM:CECI},
language = {Anglais},
journal = {{Physical review B}},
volume = {97},
number = {11},
pages = {115145},
issn = {2469-9969},
doi = {10.1103/physrevb.97.115145},
publisher = {American Physical Society (APS)},
year = {2018},
url = {http://hdl.handle.net/2078.1/199543}}

M. van Setten, M. Giantomassi, E. Bousquet, M. J. Verstraete, D. R. Hamann, X. Gonze, and G. Rignanese, « The PseudoDojo: Training and grading a 85 element optimized norm-conserving pseudopotential table, » Computer Physics Communications, vol. 226, 2018.
[Bibtex]

@article{vansetten2018,
title = {{The PseudoDojo: Training and grading a 85 element optimized norm-conserving pseudopotential table}},
author = {van Setten, Michiel and Giantomassi, Matteo and Bousquet, Eric and Verstraete, Matthieu J. and Hamann, Donald R. and Gonze, Xavier and Rignanese, Gian-Marco},
abstract = {First-principles calculations in crystalline structures are often performed with a planewave basis set. To make the number of basis functions tractable two approximations are usually introduced: core electrons are frozen and the diverging Coulomb potential near the nucleus is replaced by a smoother expression. The norm-conserving pseudopotential was the first successful method to apply these approximations in a fully ab initio way. Later on, more efficient and more exact approaches were developed based on the ultrasoft and the projector augmented wave formalisms. These formalisms are however more complex and developing new features in these frameworks is usually more difficult than in the norm-conserving framework. Most of the existing tables of norm-conserving pseudopotentials, generated long ago, do not include the latest developments, are not systematically tested or are not designed primarily for high precision. In this paper, we present our PseudoDojo framework for developing and testing full tables of pseudopotentials, and demonstrate it with a new table generated with the ONCVPSP approach. The PseudoDojo is an open source project, building on the AbiPy package, for developing and systematically testing pseudopotentials. At present it contains 7 different batteries of tests executed with ABINIT, which are performed as a function of the energy cutoff. The results of these tests are then used to provide hints for the energy cutoff for actual production calculations. Our final set contains 141 pseudopotentials split into a standard and a stringent accuracy table. In total around 70.000 calculations were performed to test the pseudopotentials. The process of developing the final table led to new insights into the effects of both the core-valence partitioning and the non-linear core corrections on the stability, convergence, and transferability of norm-conserving pseudopotentials. The PseudoDojo hence provides a set of pseudopotentials and general purpose tools for further testing and development, focusing of highly accurate calculations and their use in the development of ab initio packages. The pseudopotential files are available on the PseudoDojo web-interface www.pseudo-dojo.org under the name NC (ONCVPSP) v0.4 in the psp8, UPF2, and PSML 1.1 formats. The webinterface also provides the inputs, which are compatible with the 3.3.1 and higher versions of ONCVPSP. All tests have been performed with ABINIT 8.4.},
Keywords = {IMCN/NAPS , CECI/CISM , ZENOBE , First-principles calculation , Electronic structure , Density Functional Theory , Pseudopotential},
language = {Anglais},
journal = {{Computer Physics Communications}},
volume = {226},
issn = {0010-4655},
doi = {10.1016/j.cpc.2018.01.012},
year = {2018},
url = {http://hdl.handle.net/2078.1/193346}}

X. Gonze, J. S. Zhou, and L. Reining, « Variations on the « exact factorization » theme, » The European Physical Journal B, vol. 91, iss. 10, 2018.
[Bibtex]

@article{gonze2018,
title = {Variations on the "exact factorization" theme},
author = {Gonze, Xavier and Zhou, Jianqiang Sky and Reining, Lucia},
abstract = {In a series of publications, Hardy Gross and co-workers have highlighted the interest of an �exact factorization� approach to the interacting electron-nuclei problem, be it time-independent or time-dependent. In this approach an effective potential governs the dynamics of the nuclei such that the resulting N-body nuclear density is in principle exact. This contrasts with the more usual adiabatic approach, where the effective potential leads to an approximate nuclear density. Inspired by discussions with Hardy, we explore the factorization idea for arbitrary many-body Hamiltonians, generalizing the electron-nuclei case, with a focus on the static case. While the exact equations do not lead to any practical advantage, they are illuminating, and may therefore constitute a suitable starting point for approximations. In particular, we find that unitary transformations that diagonalize the coupling term for one of the sub-systems make exact factorization appealing. The algorithms by which the equations for the separate subsystems can be solved in the time-independent case are also explored. We illustrate our discussions using the two-site Holstein model and the quantum Rabi model. Two factorization schemes are possible: one where the boson field feels a potential determined by the electrons, and the reverse exact factorization, where the electrons feel a potential determined by the bosons; both are explored in this work. A comparison with a self-energy approach is also presented.},
Keywords = {Electronic , Optical and Magnetic Materials , Condensed Matter Physics},
language = {Anglais},
journal = {{The European Physical Journal B}},
volume = {91},
number = {10},
issn = {1434-6036},
doi = {10.1140/epjb/e2018-90278-2},
publisher = {Springer Nature America, Inc},
year = {2018},
url = {http://hdl.handle.net/2078.1/214079}}

N. A. Pike, A. Dewandre, B. Van Troeye, X. Gonze, and M. J. Verstraete, « Vibrational and dielectric properties of the bulk transition metal dichalcogenides, » Physical Review Materials, vol. 2, iss. 6, p. 63608, 2018.
[Bibtex]

@article{pike2018,
title = {Vibrational and dielectric properties of the bulk transition metal dichalcogenides},
author = {Pike, Nicholas A. and Dewandre, Antoine and Van Troeye, Beno�t and Gonze, Xavier and Verstraete, Matthieu J.},
abstract = {Interest in the bulk transition metal dichalcogenides for their electronic, photovoltaic, and optical properties has grown and led to their use in many technological applications. We present a systematic investigation of their interlinked vibrational and dielectric properties using density functional theory and density functional perturbation theory, studying the effects of the spin-orbit interaction and of the long-range e? - e? correlation as part of our investigation. This study confirms that the spin-orbit interaction plays a small role in these physical properties, while the direct contribution of dispersion corrections is of crucial importance in the description of the interatomic force constants. Here, our analysis of the structural and vibrational properties, including the Raman spectra, compare well to experimental measurement. Three materials with different point groups are showcased, and data trends on the full set of 15 existing hexagonal, trigonal, and triclinic materials are demonstrated. This overall picture will enable the modeling of devices composed of these materials for novel applications.},
Keywords = {IMCN/NAPS , CISM:CECI},
language = {Anglais},
journal = {{Physical Review Materials}},
volume = {2},
number = {6},
pages = {063608},
issn = {2475-9953},
doi = {10.1103/physrevmaterials.2.063608},
publisher = {American Physical Society (APS)},
year = {2018},
url = {http://hdl.handle.net/2078.1/201079}}

2017

Y. Gillet, S. Kontur, M. Giantomassi, C. Draxl, and X. Gonze, « Ab Initio Approach to Second-order Resonant Raman Scattering Including Exciton-Phonon Interaction, » Scientific Reports, vol. 7, iss. 1, p. 7344, 2017.
[Bibtex]

@article{gillet2017,
title = {{Ab Initio Approach to Second-order Resonant Raman Scattering Including Exciton-Phonon Interaction}},
author = {Gillet, Yannick and Kontur, Stefan and Giantomassi, Matteo and Draxl, Claudia and Gonze, Xavier},
abstract = {Raman spectra obtained by the inelastic scattering of light by crystalline solids contain contributions from first-order vibrational processes (e.g. the emission or absorption of one phonon, a quantum of vibration) as well as higher-order processes with at least two phonons being involved. At second order, coupling with the entire phonon spectrum induces a response that may strongly depend on the excitation energy, and reflects complex processes more difficult to interpret. In particular, excitons (i.e. bound electron-hole pairs) may enhance the absorption and emission of light, and couple strongly with phonons in resonance conditions. We design and implement a first-principles methodology to compute second-order Raman scattering, incorporating dielectric responses and phonon eigenstates obtained from density-functional theory and many-body theory. We demonstrate our approach for the case of silicon, relating frequency-dependent relative Raman intensities, that are in excellent agreement with experiment, to different vibrations and regions of the Brillouin zone. We show that exciton-phonon coupling, computed from first principles, indeed strongly affects the spectrum in resonance conditions. The ability to analyze second-order Raman spectra thus provides direct insight into this interaction.},
Keywords = {IMCN/NAPS , CISM:CECI , IMCN/NAPS , CISM:CECI},
language = {Anglais},
journal = {{Scientific Reports}},
volume = {7},
number = {1},
pages = {7344},
issn = {2045-2322},
doi = {10.1038/s41598-017-07682-y},
publisher = {Springer Nature},
year = {2017},
url = {http://hdl.handle.net/2078.1/195877}}

Y. Jia, S. Poncé, A. Miglio, M. Mikami, and X. Gonze, « Assessment of First-Principles and Semiempirical Methodologies for Absorption and Emission Energies of Ce3+ -Doped Luminescent Materials, » Advanced Optical Materials, vol. 5, iss. 7, p. 1600997, 2017.
[Bibtex]

@article{jia2017a,
title = {{Assessment of First-Principles and Semiempirical Methodologies for Absorption and Emission Energies of Ce3+
-Doped Luminescent Materials}},
author = {Jia, Yongchao and Ponc\'e, Samuel and Miglio, Anna and Mikami, Masayoshi and Gonze, Xavier},
abstract = {In search of a reliable methodology for the prediction of light absorption and emission of Ce3+-doped luminescent materials, 13 representative materials are studied with first-principles and semiempirical approaches. In the first-principles approach, that combines constrained density-functional theory and ?SCF, the atomic positions are obtained for both ground and excited states of the Ce3+ ion. The structural information is fed into Dorenbos' semiempirical model. Absorption and emission energies are calculated with both methods and compared with experiment. The first-principles approach matches experiment within 0.3 eV, with two exceptions at 0.5 eV. In contrast, the semiempirical approach does not perform as well (usually more than 0.5 eV error). The general applicability of the present first-principles scheme, with an encouraging predictive power, opens a novel avenue for crystal site engineering and high-throughput search for new phosphors and scintillators.},
Keywords = {IMCN/NAPS , CISM:CECI , IMCN/NAPS , CISM:CECI},
language = {Anglais},
journal = {{Advanced Optical Materials}},
volume = {5},
number = {7},
pages = {1600997},
issn = {2195-1071},
doi = {10.1002/adom.201600997},
publisher = {Wiley-Blackwell},
year = {2017},
url = {http://hdl.handle.net/2078.1/195876}}

M. van Setten, M. Giantomassi, X. Gonze, G. Rignanese, and G. Hautier, « Automation methodologies and large-scale validation for GW: Towards high-throughput GW calculations, » Physical review B, vol. 96, iss. 15, p. 155207, 2017.
[Bibtex]

@article{vansetten2017,
title = {{Automation methodologies and large-scale validation for GW: Towards high-throughput GW calculations}},
author = {van Setten, Michiel and Giantomassi, Matteo and Gonze, Xavier and Rignanese, Gian-Marco and Hautier, Geoffroy},
abstract = {The search for new materials based on computational screening relies on methods that accurately predict, in an automatic manner, total energy, atomic-scale geometries, and other fundamental characteristics of materials. Many technologically important material properties directly stem from the electronic structure of a material, but the usualworkhorse for total energies, namely density-functional theory, is plagued by fundamental shortcomings and errors from approximate exchange-correlation functionals in its prediction of the electronic structure. At variance, the GW method is currently the state-of-the-art ab initio approach for accurate electronic structure. It is mostly used to perturbatively correct density-functional theory results, but is, however, computationally demanding and also requires expert knowledge to give accurate results. Accordingly, it is not presently used in high-throughput screening: fully automatized algorithms for setting up the calculations and determining convergence are lacking. In this paper, we develop such a method and, as a first application, use it to validate the accuracy of G0W0 using the PBE starting point and the Godby-Needs plasmon-pole model (G0 WGN0 @PBE) on a set of about 80 solids. The results of the automatic convergence study utilized provide valuable insights. Indeed, we find correlations between computational parameters that can be used to further improve the automatization of GW calculations. Moreover, we find that G0 WGN0 @PBE shows a correlation between the PBE and the G0 WGN0 @PBE gaps that is much stronger than that between GW and experimental gaps. However, the G0 WGN0 @PBE gaps still describe the experimental gaps more accurately than a linear model based on the PBE gaps. With this paper, we hence show that GW can be made automatic and is more accurate than using an empirical correction of the PBE gap, but that, for accurate predictive results for a broad class of materials, an improved starting point or some type of self-consistency is necessary.},
Keywords = {IMCN/NAPS},
language = {Anglais},
journal = {{Physical review B}},
volume = {96},
number = {15},
pages = {155207},
issn = {2469-9969},
doi = {10.1103/PhysRevB.96.155207},
year = {2017},
url = {http://hdl.handle.net/2078.1/188241}}

B. Van Troeye, M. van Setten, M. Giantomassi, M. Torrent, G. Rignanese, and X. Gonze, « First-principles study of paraelectric and ferroelectric CsH2PO4 including dispersion forces: Stability and related vibrational, dielectric, and elastic properties, » Physical review. B, Condensed matter and materials physics, vol. 95, iss. 2, p. 24112, 2017.
[Bibtex]

@article{vantroeye2017,
title = {{First-principles study of paraelectric and ferroelectric CsH2PO4 including dispersion forces: Stability and related vibrational, dielectric, and elastic properties}},
author = {Van Troeye, Beno�t and van Setten, Michiel and Giantomassi, Matteo and Torrent, Marc and Rignanese, Gian-Marco and Gonze, Xavier},
abstract = {Using density functional theory (DFT) and density functional perturbation theory (DFPT), we investigate the stability and response functions of CsH2PO4, a ferroelectric material at low temperature. This material cannot be described properly by the usual (semi)local approximations within DFT. The long-range e?-e? correlation needs to be properly taken into account, using, for instance, Grimme�s DFT-D methods, as investigated in this work. We find that DFT-D3(BJ) performs the best for the members of the dihydrogenated alkali phosphate family (KH2PO4, RbH2PO4, CsH2PO4), leading to experimental lattice parameters reproduced with an average deviation of 0.5%. With these DFT-D methods, the structural, dielectric, vibrational, and mechanical properties of CsH2PO4 are globally in excellent agreement with the available experiments (<2% MAPE for Raman-active phonons). Our study suggests the possible existence of a new low-temperature phase of CsH2PO4, not yet reported experimentally. Finally, we report the implementation of DFT-D contributions to elastic constants within DFPT.},
Keywords = {IMCN/NAPS , CISM:CECI},
language = {Anglais},
journal = {{Physical review. B, Condensed matter and materials physics}},
volume = {95},
number = {2},
pages = {024112},
issn = {1550-235X},
doi = {10.1103/PhysRevB.95.024112},
publisher = {American institute of physics},
year = {2017},
url = {http://hdl.handle.net/2078.1/181859}}

Y. Jia, A. Miglio, S. Poncé, M. Mikami, and X. Gonze, "First-principles study of the luminescence of Eu2+-doped phosphors," Physical review B, vol. 96, iss. 12, p. 125132, 2017.
[Bibtex]

@article{jia2017,
title = {{First-principles study of the luminescence of Eu2+-doped phosphors}},
author = {Jia, Yongchao and Miglio, Anna and Ponc\'e, Samuel and Mikami, Masayoshi and Gonze, Xavier},
abstract = {The luminescence of fifteen representative Eu2+-doped phosphors used for white-LED and scintillation applications is studied through a Constrained Density Functional Theory. Transition energies and Stokes shift are deduced from differences of total energies between the ground and excited states of the systems, in the absorption and emission geometries. The general applicability of such methodology is first assessed: for this representative set, the calculated absolute error with respect to experiment on absorption and emission energies is within 0.3 eV. This set of compounds covers a wide range of transition energies that extents from 1.7 to 3.5 eV. The information gained from the relaxed geometries and total energies is further used to evaluate the thermal barrier for the 4f?5d crossover, the full width at half-maximum of the emission spectrum and the temperature shift of the emission peak, using a one-dimensional configuration-coordinate model. The former results indicate that the 4f?5d crossover cannot be the dominant mechanism for the thermal quenching behavior of Eu2+-doped phosphors and the latter results are compared to available experimental data and yield a 30% mean absolute relative error. Finally, a semi-empirical model used previously for Ce3+-doped hosts is adapted to Eu2+-doped hosts and gives the absorption and emission energies within 0.9 eV of experiment, underperforming compared to the first-principles calculation.},
Keywords = {IMCN/NAPS , CISM:CECI , IMCN/NAPS , CISM:CECI},
language = {Anglais},
journal = {{Physical review B}},
volume = {96},
number = {12},
pages = {125132},
issn = {2469-9969},
doi = {10.1103/physrevb.96.125132},
publisher = {American Physical Society (APS)},
year = {2017},
url = {http://hdl.handle.net/2078.1/195878}}

N. A. Pike, B. Van Troeye, A. Dewandre, G. Petretto, X. Gonze, G. Rignanese, and M. J. Verstraete, "Origin of the counterintuitive dynamic charge in the transition metal dichalcogenides," Physical review B, vol. 95, iss. 20, p. 2201106-1 - 2201106-6, 2017.
[Bibtex]

@article{pike2017,
title = {Origin of the counterintuitive dynamic charge in the transition metal dichalcogenides},
author = {Pike, Nicholas A. and Van Troeye, Beno�t and Dewandre, Antoine and Petretto, Guido and Gonze, Xavier and Rignanese, Gian-Marco and Verstraete, Matthieu J.},
abstract = {Despite numerous studies of transition metal dichalcogenides, the diversity of their chemical bonding characteristics and charge transfer is not well understood. Based on density functional theory we investigate their static and dynamic charges. The dynamic charge of the transition metal dichalcogenides with trigonal symmetry are anomalously large, while in their hexagonally symmetric counterparts, we even observe a counterintuitive sign, i.e., the transition metal takes a negative charge, opposite to its static charge. This phenomenon, so far never remarked on or analyzed, is understood by investigating the perturbative response of the system and by investigating the hybridization of the molecular orbitals near the Fermi level. Furthermore, a link is established between the sign of the Born effective charge and the process of ? backbonding from organic chemistry. Experiments are proposed to verify the calculated sign of the dynamical charge in these materials. Employing a high-throughput search we also identify other materials that present counterintuitive dynamic charges.},
Keywords = {IMCN/NAPS , CISM:CECI},
language = {Anglais},
journal = {{Physical review B}},
volume = {95},
number = {20},
pages = {2201106-1 - 2201106-6},
issn = {2469-9969},
doi = {10.1103/PhysRevB.95.201106},
year = {2017},
url = {http://hdl.handle.net/2078.1/185375}}

D. Waroquiers, X. Gonze, G. Rignanese, C. Welker-Nieuwoudt, F. Rosowski, M. Göbel, S. Schenk, P. Degelmann, R. André, R. Glaum, and G. Hautier, "Statistical Analysis of Coordination Environments in Oxides," Chemistry of Materials, vol. 29, iss. 19, pp. 8346-8360, 2017.
[Bibtex]

@article{waroquiers2017,
title = {{Statistical Analysis of Coordination Environments in Oxides}},
author = {Waroquiers, David and Gonze, Xavier and Rignanese, Gian-Marco and Welker-Nieuwoudt, Cathrin and Rosowski, Frank and G\"obel, Michael and Schenk, Stephan and Degelmann, Peter and Andr\'e, Rute and Glaum, Robert and Hautier, Geoffroy},
abstract = {Coordination or local environments (e.g., tetrahedra and octahedra) are powerful descriptors of the crystalline structure of materials. These structural descriptors are essential to the understanding of crystal chemistry and the design of new materials. However, extensive statistics on the occurrence of local environment are not available even on common chemistries such as oxides. Here, we present the first large-scale statistical analysis of the coordination environments of cations in oxides using a large set of experimentally observed compounds (about 8000). Using a newly developed method, we provide the distribution of local environment for each cation in oxides. We discuss our results highlighting previously known trends and unexpected coordination environments, as well as compounds presenting very rare coordinations. Our work complements the know-how of the solid state chemist with a statistically sound analysis and paves the way for further data mining efforts linking, for instance, coordination environments to materials properties.},
Keywords = {IMCN / NAPS , CISM:CECI},
language = {Anglais},
journal = {{Chemistry of Materials}},
volume = {29},
number = {19},
pages = {8346-8360},
issn = {1520-5002},
doi = {10.1021/acs.chemmater.7b02766},
publisher = {American Chemical Society},
year = {2017},
url = {http://hdl.handle.net/2078.1/188153}}

2016

E. del Corro, A. R. Botello Méndez, Y. Gillet, A. L. Elias, H. Terrones, S. Feng, C. Fantini, D. Rhodes, N. Pradhan, L. Balicas, X. Gonze, J. Charlier, M. Terrones, and M. A. Pimenta, "Atypical Exciton-Phonon Interactions in WS2 and WSe2 Monolayers Revealed by Resonance Raman Spectroscopy," Nano Letters : a journal dedicated to nanoscience and nanotechnology, vol. 16, iss. 4, pp. 2363-2368, 2016.
[Bibtex]

@article{delcorro2016,
title = {{Atypical Exciton-Phonon Interactions in WS2 and WSe2 Monolayers Revealed by Resonance Raman Spectroscopy}},
author = {del Corro, Elena and Botello M\'endez, Andr�s Rafael and Gillet, Yannick and Elias, Ana Laura and Terrones, Humberto and Feng, Simin and Fantini, Cristiano and Rhodes, Daniel and Pradhan, Narayan and Balicas, Luis and Gonze, Xavier and Charlier, Jean-Christophe and Terrones, Mauricio and Pimenta, Marcos A.},
abstract = {Resonant Raman spectroscopy is a powerful tool for providing information about excitons and exciton�phonon coupling in two-dimensional materials. We present here resonant Raman experiments of single-layered WS2 and WSe2 using more than 25 laser lines. The Raman excitation profiles of both materials show unexpected differences. All Raman features of WS2 monolayers are enhanced by the first-optical excitations (with an asymmetric response for the spin�orbit related XA and XB excitons), whereas Raman bands of WSe2 are not enhanced at XA/B energies. Such an intriguing phenomenon is addressed by DFT calculations and by solving the Bethe-Salpeter equation. These two materials are very similar. They prefer the same crystal arrangement, and their electronic structure is akin, with comparable spin�orbit coupling. However, we reveal that WS2 and WSe2 exhibit quite different exciton�phonon interactions. In this sense, we demonstrate that the interaction between XC and XA excitons with phonons explains the different Raman responses of WS2 and WSe2, and the absence of Raman enhancement for the WSe2 modes at XA/B energies. These results reveal unusual exciton�phonon interactions and open new avenues for understanding the two-dimensional materials physics, where weak interactions play a key role coupling different degrees of freedom (spin, optic, and electronic).},
Keywords = {CISM:CECI , Two-dimensional materials , Transition metal dichalcogenides , Resonant Raman spectroscopy , First-principles calculations , Exciton-phonon interaction},
language = {Anglais},
journal = {{Nano Letters : a journal dedicated to nanoscience and nanotechnology}},
volume = {16},
number = {4},
pages = {2363-2368},
issn = {1530-6992},
doi = {10.1021/acs.nanolett.5b05096},
publisher = {American Chemical Society},
year = {2016},
url = {http://hdl.handle.net/2078.1/173451}}

Y. Gillet, M. Giantomassi, and X. Gonze, "Efficient on-the-fly interpolation technique for Bethe-Salpeter calculations of optical spectra," Computer Physics Communications, vol. 203C, pp. 83-93, 2016.
[Bibtex]

@article{gillet2016,
title = {Efficient on-the-fly interpolation technique for {Bethe-Salpeter} calculations of optical spectra},
author = {Gillet, Yannick and Giantomassi, Matteo and Gonze, Xavier},
abstract = {The Bethe�Salpeter formalism represents the most accurate method available nowadays for computing neutral excitation energies and optical spectra of crystalline systems from first principles. Bethe�Salpeter calculations yield very good agreement with experiment but are notoriously difficult to converge with respect to the sampling of the electronic wavevectors. Well-converged spectra therefore require significant computational and memory resources, even by today�s standards. These bottlenecks hinder the investigation of systems of great technological interest. They are also barriers to the study of derived quantities like piezoreflectance, thermoreflectance or resonant Raman intensities. We present a new methodology that decreases the workload needed to reach a given accuracy. It is based on a double-grid on-the-fly interpolation within the Brillouin zone, combined with the Lanczos algorithm. It achieves significant speed-up and reduction of memory requirements. The technique is benchmarked in terms of accuracy on silicon, gallium arsenide and lithium fluoride. The scaling of the performance of the method as a function of the Brillouin Zone point density is much better than a conventional implementation. We also compare our method with other similar techniques proposed in the literature.},
Keywords = {CISM:CECI , IMCN/NAPS},
language = {Anglais},
journal = {{Computer Physics Communications}},
volume = {203C},
pages = {83-93},
issn = {1879-2944},
doi = {10.1016/j.cpc.2016.02.008},
address = {Amsterdam},
publisher = {Elsevier BV * North-Holland},
year = {2016},
url = {http://hdl.handle.net/2078.1/173172}}

S. Poyyapakkam Ramkumar, Y. Gillet, A. Miglio, M. van Setten, X. Gonze, and G. Rignanese, "First-principles investigation of the structural, dynamical, and dielectric properties of kesterite, stannite, and PMCA phases of Cu2ZnSnS4," Physical review B, vol. 94, iss. 224302, pp. 1-10, 2016.
[Bibtex]

@article{ramkumar2016,
title = {{First-principles investigation of the structural, dynamical, and dielectric properties of kesterite, stannite, and PMCA phases of Cu2ZnSnS4}},
author = {Poyyapakkam Ramkumar, Sriram and Gillet, Yannick and Miglio, Anna and van Setten, Michiel and Gonze, Xavier and Rignanese, Gian-Marco},
abstract = {Cu2ZnSnS4 (CZTS) is a promising material as an absorber in photovoltaic applications. The measured efficiency, however, is far from the theoretically predicted value for the known CZTS phases. To improve the understanding of this discrepancy, we investigate the structural, dynamical, and dielectric properties of the three main phases of CZTS (kesterite, stannite, and PMCA) using density functional perturbation theory (DFPT). The effect of the exchange-correlation functional on the computed properties is analyzed. A qualitative agreement of the theoretical Raman spectrum with measurements is observed. However, none of the phases correspond to the experimental spectrum within the error bar that is usually to be expected for DFPT. This corroborates the need to consider cation disorder and other lattice defects extensively in this material.},
Keywords = {IMCN / NAPS , CISM:CECI},
language = {Anglais},
journal = {{Physical review B}},
volume = {94},
number = {224302},
pages = {1-10},
issn = {1550-235X},
doi = {10.1103/PhysRevB.94.224302},
publisher = {American Physical Society},
year = {2016},
url = {http://hdl.handle.net/2078.1/179027}}

Y. Jia, A. Miglio, S. Poncé, X. Gonze, and M. Mikami, "First-principles study of Ce3+-doped lanthanum silicate nitride phosphors: Neutral excitation, Stokes shift, and luminescent center identification," Physical review. B, Condensed matter and materials physics, vol. 93, iss. 15, p. 155111, 2016.
[Bibtex]

@article{jia2016,
title = {{First-principles study of Ce3+-doped lanthanum silicate nitride phosphors: Neutral excitation, Stokes shift, and luminescent center identification}},
author = {Jia, Yongchao and Miglio, Anna and Ponc\'e, Samuel and Gonze, Xavier and Mikami, Masayoshi},
abstract = {We study from first principles two lanthanum silicate nitride compounds, LaSi3N5 and La3Si6N11, pristine as well as doped with Ce3+ ion, in view of explaining their different emission color, and characterizing the luminescent center. The electronic structures of the two undoped hosts are similar, and do not give a hint to quantitatively describe such difference. The 4f ? 5d neutral excitation of the Ce3+ ions is simulated through a constrained density functional theory method coupled with a SCF analysis of total energies, yielding absorption energies. Afterwards, atomic positions in the excited state are relaxed, yielding the emission energies and Stokes shifts. Based on these results, the luminescent centers in LaSi3N5:Ce and La3Si6N11:Ce are identified. The agreement with the experimental data for the computed quantities is quite reasonable and explains the different color of the emitted light. Also, the Stokes shifts are obtained within 20% difference relative to experimental data.},
Keywords = {IMCN/NAPS , CISM:CECI},
language = {Anglais},
journal = {{Physical review. B, Condensed matter and materials physics}},
volume = {93},
number = {15},
pages = {155111},
issn = {1550-235X},
doi = {10.1103/PhysRevB.93.155111},
publisher = {American institute of physics},
year = {2016},
url = {http://hdl.handle.net/2078.1/183061}}

B. Van Troeye, M. Torrent, and X. Gonze, "Interatomic force constants including the DFT-D dispersion contribution," Physical review. B, Condensed matter and materials physics, vol. 93, iss. 14, p. 144304, 2016.
[Bibtex]

@article{vantroeye2016,
title = {{Interatomic force constants including the DFT-D dispersion contribution}},
author = {Van Troeye, Beno�t and Torrent, Marc and Gonze, Xavier},
abstract = {Grimme�s DFT-D dispersion contribution to interatomic forces constants, required for the computation of the phonon band structures in density-functional perturbation theory, has been derived analytically. The implementation has then been validated with respect to frozen phonons, and applied on materials where weak cohesive forces play a major role, i.e., argon, graphite, benzene, etc. We show that these dispersive contributions have to be considered to properly reproduce the experimental vibrational properties of these materials, although the lattice parameter change, coming from the ground-state relaxation with the proper functional, induces the most important change with respect to a treatment without dispersion corrections. In the current implementation, the contribution of these dispersion corrections to the dynamical matrices (with a number of elements that is proportional to the square of the number of atoms) has only a cubic scaling with the number of atoms. In practice, the overload with respect to density-functional calculations is small, making this methodology promising to study vibrational properties of large dispersive systems.},
Keywords = {IMCN/NAPS , CISM:CECI},
language = {Anglais},
journal = {{Physical review. B, Condensed matter and materials physics}},
volume = {93},
number = {14},
pages = {144304},
issn = {1550-235X},
doi = {10.1103/PhysRevB.93.144304},
publisher = {American institute of physics},
year = {2016},
url = {http://hdl.handle.net/2078.1/173532}}

J. Laflamme Janssen, Y. Gillet, S. Poncé, A. Martin, M. Torrent, and X. Gonze, "Precise effective masses from density functional perturbation theory," Physical review. B, Condensed matter and materials physics, vol. 93, iss. 20, p. 205147, 2016.
[Bibtex]

@article{laflamme2016,
title = {Precise effective masses from density functional perturbation theory},
author = {Laflamme Janssen, Jonathan and Gillet, Yannick and Ponc\'e, Samuel and Martin, Alexandre and Torrent, Marc and Gonze, Xavier},
abstract = {The knowledge of effective masses is a key ingredient to analyze numerous properties of semiconductors, like carrier mobilities, (magneto)transport properties, or band extrema characteristics yielding carrier densities and density of states. Currently, these masses are usually calculated using finite-difference estimation of density functional theory (DFT) electronic band curvatures. However, finite differences require an additional convergence study and are prone to numerical noise. Moreover, the concept of effective mass breaks down at degenerate band extrema. We assess the former limitation by developing a method that allows to obtain the Hessian of DFT bands directly, using density functional perturbation theory. Then, we solve the latter issue by adapting the concept of "transport equivalent effective mass" to the k�p framework. The numerical noise inherent to finite-difference methods is thus eliminated, along with the associated convergence study. The resulting method is therefore more general, more robust, and simpler to use, which makes it especially appropriate for high-throughput computing. After validating the developed techniques, we apply them to the study of silicon, graphane, and arsenic. The formalism is implemented into the abinit software and supports the norm-conserving pseudopotential approach, the projector augmented-wave method, and the inclusion of spin-orbit coupling. The derived expressions also apply to the ultrasoft pseudopotential method.},
Keywords = {CISM:CECI},
language = {Anglais},
journal = {{Physical review. B, Condensed matter and materials physics}},
volume = {93},
number = {20},
pages = {205147},
issn = {1550-235X},
doi = {10.1103/PhysRevB.93.205147},
publisher = {American institute of physics},
year = {2016},
url = {http://hdl.handle.net/2078.1/174483}}

X. Gonze, F. Jollet, F. M. Abreu Araujo, D. Adams, B. Amadon, T. Applencourt, C. Audouze, J. Beuken, J. Bieder, A. Bokhanchuk, E. Bousquet, F. Bruneval, D. Caliste, M. Côté, F. Dahm, F. Da Pieve, M. Delaveau, M. Di Gennaro, B. Dorado, C. Espejo, G. Geneste, L. Genovese, A. Gerossier, M. Giantomassi, Y. Gillet, D. R. Hamann, L. He, G. Jomard, J. Laflamme Janssen, S. Le Roux, A. Levitt, A. Lherbier, F. Liu, I. Lukacevic, A. Martin, C. Martins, M. J. T. Oliveira, S. Poncé, Y. Pouillon, T. Rangel, G. Rignanese, A. H. Romero, B. Rousseau, O. Rubel, A. A. Shukri, M. Stankovski, M. Torrent, M. van Setten, B. Van Troeye, M. J. Verstraete, D. Waroquiers, J. Wiktor, B. Xu, A. Zhou, and J. W. Zwanziger, "Recent developments in the ABINIT software package," Computer Physics Communications, vol. 205, pp. 106-131, 2016.
[Bibtex]

@article{gonze2016,
title = {{Recent developments in the ABINIT software package}},
author = {Gonze, Xavier and Jollet, F. and Abreu Araujo, Flavio Miguel and Adams, D. and Amadon, B. and Applencourt, T. and Audouze, C. and Beuken, Jean-Michel and Bieder, J. and Bokhanchuk, A. and Bousquet, E. and Bruneval, F. and Caliste, D. and C\^ot\'e, M. and Dahm, F. and Da Pieve, Fabiana and Delaveau, M. and Di Gennaro, M. and Dorado, B. and Espejo, C. and Geneste, G. and Genovese, L. and Gerossier, A. and Giantomassi, Matteo and Gillet, Yannick and Hamann, D.R. and He, L. and Jomard, G. and Laflamme Janssen, Jonathan and Le Roux, St�phane and Levitt, A. and Lherbier, Aur�lien and Liu, F. and Lukacevic, I. and Martin, A. and Martins, C. and Oliveira, M.J.T. and Ponc\'e, Samuel and Pouillon, Y. and Rangel, T. and Rignanese, Gian-Marco and Romero, A.H. and Rousseau, B. and Rubel, O. and Shukri, A.A. and Stankovski, M. and Torrent, M. and van Setten, Michiel and Van Troeye, Beno�t and Verstraete, M.J. and Waroquiers, David and Wiktor, J. and Xu, B. and Zhou, A. and Zwanziger, J.W.},
abstract = {ABINIT is a package whose main program allows one to find the total energy, charge density, electronic structure and many other properties of systems made of electrons and nuclei, (molecules and periodic solids) within Density Functional Theory (DFT), Many-Body Perturbation Theory (GW approximation and Bethe�Salpeter equation) and Dynamical Mean Field Theory (DMFT). ABINIT also allows to optimize the geometry according to the DFT forces and stresses, to perform molecular dynamics simulations using these forces, and to generate dynamical matrices, Born effective charges and dielectric tensors. The present paper aims to describe the new capabilities of ABINIT that have been developed since 2009. It covers both physical and technical developments inside the ABINIT code, as well as developments provided within the ABINIT package. The developments are described with relevant references, input variables, tests and tutorials.},
Keywords = {IMCN/NAPS , CISM:CECI},
language = {Anglais},
journal = {{Computer Physics Communications}},
volume = {205},
pages = {106-131},
issn = {1879-2944},
doi = {10.1016/j.cpc.2016.04.003},
address = {Amsterdam},
publisher = {Elsevier BV * North-Holland},
year = {2016},
url = {http://hdl.handle.net/2078.1/174586}}

K. Lejaeghere, G. Bihlmayer, T. Bjorkman, P. Blaha, S. Blugel, V. Blum, D. Caliste, I. E. Castelli, S. J. Clark, A. Dal Corso, S. de Gironcoli, T. Deutsch, J. K. Dewhurst, I. Di Marco, C. Draxl, M. Dulak, O. Eriksson, J. A. Flores-Livas, K. F. Garrity, L. Genovese, P. Giannozzi, M. Giantomassi, S. Goedecker, X. Gonze, O. Granas, E. K. U. Gross, A. Gulans, F. Gygi, D. R. Hamann, P. J. Hasnip, N. A. W. Holzwarth, D. Iusan, D. B. Jochym, F. Jollet, D. Jones, G. Kresse, K. Koepernik, E. Kucukbenli, Y. O. Kvashnin, I. L. M. Locht, S. Lubeck, M. Marsman, N. Marzari, U. Nitzsche, L. Nordstrom, T. Ozaki, L. Paulatto, C. J. Pickard, W. Poelmans, M. I. J. Probert, K. Refson, M. Richter, G. Rignanese, S. Saha, M. Scheffler, M. Schlipf, K. Schwarz, S. Sharma, F. Tavazza, P. Thunstrom, A. Tkatchenko, M. Torrent, D. Vanderbilt, M. van Setten, V. Van Speybroeck, J. M. Wills, J. R. Yates, G. -X. Zhang, and S. Cottenier, "Reproducibility in density functional theory calculations of solids," Science, vol. 351, iss. 6280, p. aad3000-aad3000, 2016.
[Bibtex]

@article{lejaeghere2016,
title = {Reproducibility in density functional theory calculations of solids},
author = {Lejaeghere, K. and Bihlmayer, G. and Bjorkman, T. and Blaha, P. and Blugel, S. and Blum, V. and Caliste, D. and Castelli, I. E. and Clark, S. J. and Dal Corso, A. and de Gironcoli, S. and Deutsch, T. and Dewhurst, J. K. and Di Marco, I. and Draxl, C. and Dulak, M. and Eriksson, O. and Flores-Livas, J. A. and Garrity, K. F. and Genovese, L. and Giannozzi, P. and Giantomassi, Matteo and Goedecker, S. and Gonze, Xavier and Granas, O. and Gross, E. K. U. and Gulans, A. and Gygi, F. and Hamann, D. R. and Hasnip, P. J. and Holzwarth, N. A. W. and Iusan, D. and Jochym, D. B. and Jollet, F. and Jones, D. and Kresse, G. and Koepernik, K. and Kucukbenli, E. and Kvashnin, Y. O. and Locht, I. L. M. and Lubeck, S. and Marsman, M. and Marzari, N. and Nitzsche, U. and Nordstrom, L. and Ozaki, T. and Paulatto, L. and Pickard, C. J. and Poelmans, W. and Probert, M. I. J. and Refson, K. and Richter, M. and Rignanese, Gian-Marco and Saha, S. and Scheffler, M. and Schlipf, M. and Schwarz, K. and Sharma, S. and Tavazza, F. and Thunstrom, P. and Tkatchenko, A. and Torrent, M. and Vanderbilt, D. and van Setten, Michiel and Van Speybroeck, V. and Wills, J. M. and Yates, J. R. and Zhang, G.-X. and Cottenier, S.},
abstract = {The widespread popularity of density functional theory has given rise to an extensive range of dedicated codes for predicting molecular and crystalline properties. However, each code implements the formalism in a different way, raising questions about the reproducibility of such predictions. We report the results of a community-wide effort that compared 15 solid-state codes, using 40 different potentials or basis set types, to assess the quality of the Perdew-Burke-Ernzerhof equations of state for 71 elemental crystals. We conclude that predictions from recent codes and pseudopotentials agree very well, with pairwise differences that are comparable to those between different high-precision experiments. Older methods, however, have less precise agreement. Our benchmark provides a framework for users and developers to document the precision of new applications and methodological improvements.},
Keywords = {IMCN / NAPS , CISM:CECI},
language = {Anglais},
journal = {Science},
volume = {351},
number = {6280},
pages = {aad3000-aad3000},
issn = {1095-9203},
doi = {10.1126/science.aad3000},
address = {Washington},
publisher = {American Association for the Advancement of Science},
year = {2016},
url = {http://hdl.handle.net/2078.1/173067}}

M. C. Weber, M. Guennou, C. Toulouse, M. Cazayous, Y. Gillet, X. Gonze, and J. Kreisel, "Temperature evolution of the band gap in BiFeO3 traced by resonant Raman scattering," Physical review. B, Condensed matter and materials physics, vol. 93, iss. 12, p. 125204, 2016.
[Bibtex]

@article{weber2016,
title = {{Temperature evolution of the band gap in BiFeO3 traced by resonant Raman scattering}},
author = {Weber, Mads Christof and Guennou, Mael and Toulouse, Constance and Cazayous, Maximilien and Gillet, Yannick and Gonze, Xavier and Kreisel, Jens},
abstract = {Knowledge of the electronic band structure of multiferroic oxides, crucial for the understanding and tuning of photoinduced effects, remains very limited even in the model and thoroughly studied BiFeO3. Here, we investigate the electronic band structure of BiFeO3 using Raman scattering with twelve different excitation wavelengths ranging from the blue to the near infrared. We show that resonant Raman signatures can be assigned to direct and indirect electronic transitions, as well as in-gap electronic levels, most likely associated with oxygen vacancies. Their temperature evolution establishes that the remarkable and intriguing variation of the optical band gap can be related to the shrinking of an indirect electronic band gap, while the energies for direct electronic transitions remains nearly temperature independent.},
language = {Anglais},
journal = {{Physical review. B, Condensed matter and materials physics}},
volume = {93},
number = {12},
pages = {125204},
issn = {1550-235X},
doi = {10.1103/PhysRevB.93.125204},
publisher = {American institute of physics},
year = {2016},
url = {http://hdl.handle.net/2078.1/173026}}

S. Poncé, Y. Jia, M. Giantomassi, M. Mikami, and X. Gonze, "Understanding Thermal Quenching of Photoluminescence in Oxynitride Phosphors from First Principles," The Journal of Physical Chemistry Part C: Nanomaterials and Interfaces, vol. 120, iss. 7, pp. 4040-4047, 2016.
[Bibtex]

@article{ponce2016,
title = {{Understanding Thermal Quenching of Photoluminescence in Oxynitride Phosphors from First Principles}},
author = {Ponc\'e, Samuel and Jia, Yongchao and Giantomassi, Matteo and Mikami, Masayoshi and Gonze, Xavier},
abstract = {Understanding the physical mechanisms behind thermal effects in phosphors is crucial for white light-emitting device (WLEDs) applications, as thermal quenching of their photoluminescence might render them useless. We analyze from first-principles, before and after absorption/emission of light, two chemically close Eu-doped Ba3Si6O12N2 and Ba3Si6O9N4 crystals for WLEDs. The first one has an almost constant emission intensity with increasing temperature whereas the other one does not. Our results, in which the Eu-5d levels are obtained inside the band gap thanks to the removal of an electron from the 4f7 shell, and the atomic neighborhood properly relaxed in the excited state, attributes the above-mentioned experimental difference to an autoionization model of the thermal quenching, based on the energy difference between Eu5d and the conduction band minimum. Our depleted-shifted 4f method can identify luminescent centers and therefore allows for effective crystal site engineering of luminescent centers in phosphors from first principles},
Keywords = {IMCN/NAPS , CISM:CECI},
language = {Anglais},
journal = {{The Journal of Physical Chemistry Part C: Nanomaterials and Interfaces}},
volume = {120},
number = {7},
pages = {4040-4047},
issn = {1932-7455},
doi = {10.1021/acs.jpcc.5b12361},
publisher = {American Chemical Society},
year = {2016},
url = {http://hdl.handle.net/2078.1/183031}}

Y. Meng, X. Liu, C. Huo, W. Guo, D. Cao, Q. Peng, A. Dearden, X. Gonze, Y. Yang, J. Wang, H. Jiao, Y. Li, and X. Wen, "When Density Functional Approximations Meet Iron Oxides," Journal of Chemical Theory and Computation, vol. 12, iss. 10, pp. 5132-5144, 2016.
[Bibtex]

@article{meng2016,
title = {{When Density Functional Approximations Meet Iron Oxides}},
author = {Meng, Yu and Liu, Xing-Wu and Huo, Chun-Fang and Guo, Wen-Ping and Cao, Dong-Bo and Peng, Qing and Dearden, Albert and Gonze, Xavier and Yang, Yonh and Wang, Jianguo and Jiao, Haijun and Li, Yongwang and Wen, Xiao-Dong},
abstract = {Three density functional approximations (DFAs), PBE, PBE+U, and Heyd?Scuseria?Ernzerhof screened hybrid functional (HSE), were employed to investigate the geometric, electronic, magnetic, and thermodynamic properties of four iron oxides, namely, ?-FeOOH, ?-Fe2O3, Fe3O4, and FeO. Comparing our calculated results with available experimental data, we found that HSE (a = 0.15) (containing 15% �screened� Hartree?Fock exchange) can provide reliable values of lattice constants, Fe magnetic moments, band gaps, and formation energies of all four iron oxides, while standard HSE (a = 0.25) seriously overestimates the band gaps and formation energies. For PBE+U, a suitable U value can give quite good results for the electronic properties of each iron oxide, but it is challenging to accurately get other properties of the four iron oxides using the same U value. Subsequently, we calculated the Gibbs free energies of transformation reactions among iron oxides using the HSE (a = 0.15) functional and plotted the equilibrium phase diagrams of the iron oxide system under various conditions, which provide reliable theoretical insight into the phase transformations of iron oxides.},
Keywords = {IMCN/NAPS},
language = {Anglais},
journal = {{Journal of Chemical Theory and Computation}},
volume = {12},
number = {10},
pages = {5132-5144},
issn = {1549-9626},
doi = {10.1021/acs.jctc.6b00640},
publisher = {American Chemical Society},
year = {2016},
url = {http://hdl.handle.net/2078.1/183091}}

2015

G. Antonius, S. Poncé, E. Lantagne-Hurtubise, G. Auclair, X. Gonze, and M. Côté, "Dynamical and anharmonic effects on the electron-phonon coupling and the zero-point renormalization of the electronic structure," Physical review. B, Condensed matter and materials physics, vol. 92, iss. 8, p. 85137, 2015.
[Bibtex]

@article{antonius2015,
title = {Dynamical and anharmonic effects on the electron-phonon coupling and the zero-point renormalization of the electronic structure},
author = {Antonius, G. and Ponc\'e, Samuel and Lantagne-Hurtubise, E. and Auclair, G. and Gonze, Xavier and C\^ot\'e, M.},
abstract = {The renormalization of the band structure at zero temperature due to electron-phonon coupling is explored in diamond, BN, LiF and MgO crystals. We implement a dynamical scheme to compute the frequency-dependent self-energy and the resulting quasiparticle electronic structure. Our calculations reveal the presence of a satellite band below the Fermi level of LiF and MgO. We show that the renormalization factor (Z), which is neglected in the adiabatic approximation, can reduce the zero-point renormalization (ZPR) by as much as 40%. Anharmonic effects in the renormalized eigenvalues at finite atomic displacements are explored with the frozen-phonon method. We use a non-perturbative expression for the ZPR, going beyond the Allen-Heine-Cardona theory. Our results indicate that high-order electron-phonon coupling terms contribute significantly to the zero-point renormalization for certain materials.},
Keywords = {IMCN / NAPS},
language = {Anglais},
journal = {{Physical review. B, Condensed matter and materials physics}},
volume = {92},
number = {8},
pages = {085137},
issn = {1550-235X},
doi = {10.1103/PhysRevB.92.085137},
publisher = {American institute of physics},
year = {2015},
url = {http://hdl.handle.net/2078.1/167907}}

A. Bhatia, G. Hautier, T. Nilgianskul, A. Miglio, J. Sun, H. J. Kim, K. H. Kim, S. Chen, G. Rignanese, X. Gonze, and J. Suntivich, "High-Mobility Bismuth-based Transparent p-Type Oxide from High-Throughput Material Screening," Chemistry of Materials, vol. 28, iss. 1, pp. 30-34, 2015.
[Bibtex]

@article{bhatia2015,
title = {{High-Mobility Bismuth-based Transparent p-Type Oxide from High-Throughput Material Screening}},
author = {Bhatia, Amit and Hautier, Geoffroy and Nilgianskul, Tan and Miglio, Anna and Sun, Jingying and Kim, Hyung Joon and Kim, Kee Hoon and Chen, Shuo and Rignanese, Gian-Marco and Gonze, Xavier and Suntivich, Jin},
Keywords = {CISM:CECI , IMCN / NAPS},
language = {Anglais},
journal = {{Chemistry of Materials}},
volume = {28},
number = {1},
pages = {30-34},
issn = {1520-5002},
doi = {10.1021/acs.chemmater.5b03794},
publisher = {American Chemical Society},
year = {2015},
url = {http://hdl.handle.net/2078.1/169991}}

X. Gonze, "Le prix Nobel de Physique 2014 : "Et la lumière fut !"," Revue des Questions Scientifiques, vol. 186, iss. 4, pp. 495-518, 2015.
[Bibtex]

@article{gonze2015,
title = {{Le prix Nobel de Physique 2014 : "Et la lumi\`ere fut !"}},
author = {Gonze, Xavier},
abstract = {En octobre 2014, le prix Nobel 2014 de physique a �t� attribu� � Isamu Akasaki, Hiroshi Amano et Shuji Nakamura, pour leurs contributions d�cisives au d�veloppement des diodes �lectroluminescentes (LED) bleues de haut rendement, qui ont ouvert la voie vers les LEDs blanches efficaces et respectueuses de l�environnement. Dans l�esprit d�Alfred Nobel, les prix Nobel devaient couronner des d�couvertes ou inventions qui b�n�ficieraient au progr�s de l�humanit�. Disponibles sur le march� depuis quelques ann�es, les LEDs blanches s�imposent de plus en plus dans notre quotidien, et t�moignent de l�importance de cette perc�e technologique, bas�e directement sur l�application des principes de la physique moderne.},
Keywords = {IMCN / NAPS},
language = {Anglais},
journal = {{Revue des Questions Scientifiques}},
volume = {186},
number = {4},
pages = {495-518},
issn = {0035-2160},
publisher = {Societe Scientifique de Bruxelles},
year = {2015},
url = {http://hdl.handle.net/2078.1/171802}}

A. Marini, S. Poncé, and X. Gonze, "Many-body perturbation theory approach to the electron-phonon interaction with density-functional theory as a starting point," Physical review. B, Condensed matter and materials physics, vol. 91, iss. 22, p. 224310, 2015.
[Bibtex]

@article{marini2015,
title = {Many-body perturbation theory approach to the electron-phonon interaction with density-functional theory as a starting point},
author = {Marini, Andrea and Ponc\'e, Samuel and Gonze, Xavier},
abstract = {The electron�phonon interaction plays a crucial role in many fields of physics and chemistry. Nevertheless, its actual calculation by means of modern many�body perturbation theory is weakened by the use of model Hamiltonians that are based on parameters difficult to extract from the experiments. Such shortcoming can be bypassed by using density�functional theory to evaluate the electron�phonon scattering amplitudes, phonon frequencies and electronic bare energies. In this work, we discuss how a consistent many�body diagrammatic expansion can be constructed on top of density�functional theory. In that context, the role played by screening and self�consistency when all the components of the electron�nucleus and nucleus�nucleus interactions are taken into account is paramount. A way to avoid overscreening is notably presented. Finally, we derive cancellations rules as well as internal consistency constraints in order to draw a clear, sound and practical scheme to merge many�body perturbation and density�functional theory.},
Keywords = {IMCN / NAPS},
language = {Anglais},
journal = {{Physical review. B, Condensed matter and materials physics}},
volume = {91},
number = {22},
pages = {224310},
issn = {1550-235X},
doi = {10.1103/PhysRevB.91.224310},
publisher = {American institute of physics},
year = {2015},
url = {http://hdl.handle.net/2078.1/167906}}

S. Poncé, Y. Gillet, J. Laflamme Janssen, A. Marini, M. Verstraete, and X. Gonze, "Temperature dependence of the electronic structure of semiconductors and insulators," Journal of Chemical Physics, vol. 143, p. 102813, 2015.
[Bibtex]

@article{ponce2015,
title = {Temperature dependence of the electronic structure of semiconductors and insulators},
author = {Ponc\'e, Samuel and Gillet, Yannick and Laflamme Janssen, Jonathan and Marini, Andrea and Verstraete, Matthieu and Gonze, Xavier},
abstract = {The renormalization of electronic eigenenergies due to electron-phonon coupling (temperature dependence and zero-point motion effect) is sizable in many materials with light atoms. This effect, often neglected in ab initio calculations, can be computed using the perturbation-based Allen-Heine-Cardona theory in the adiabatic or non-adiabatic harmonic approximation. After a short description of the recent progresses in this field and a brief overview of the theory, we focus on the issue of phonon wavevector sampling convergence, until now poorly understood. Indeed, the renormalization is obtained numerically through a slowly converging q-point integration. For non-zero Born effective charges, we show that a divergence appears in the electron-phonon matrix elements at q ? ?, leading to a divergence of the adiabatic renormalization at band extrema. This problem is exacerbated by the slow convergence of Born effective charges with electronic wavevector sampling, which leaves residual Born effective charges in ab initio calculations on materials that are physically devoid of such charges. Here, we propose a solution that improves this convergence. However, for materials where Born effective charges are physically non-zero, the divergence of the renormalization indicates a breakdown of the adiabatic harmonic approximation, which we assess here by switching to the non-adiabatic harmonic approximation. Also, we study the convergence behavior of the renormalization and develop reliable extrapolation schemes to obtain the converged results. Finally, the adiabatic and non-adiabatic theories, with corrections for the slow Born effective charge convergence problem (and the associated divergence) are applied to the study of five semiconductors and insulators: ?-AlN, ?-AlN, BN, diamond, and silicon. For these five materials, we present the zero-point renormalization, temperature dependence, phonon-induced lifetime broadening, and the renormalized electronic band structure.},
Keywords = {CISM:CECI},
language = {Anglais},
journal = {{Journal of Chemical Physics}},
volume = {143},
pages = {102813},
issn = {1089-7690},
doi = {10.1063/1.4927081},
publisher = {American Institute of Physics},
year = {2015},
url = {http://hdl.handle.net/2078.1/163793}}

2014

A. Miglio, R. Saniz, D. Waroquiers, M. Stankovski, M. Giantomassi, G. Hautier, G. Rignanese, and X. Gonze, "Computed electronic and optical properties of SnO2 under compressive stress," Optical Materials, vol. 38, iss. 1, pp. 161-166, 2014.
[Bibtex]

@article{miglio2014,
title = {{Computed electronic and optical properties of SnO2 under compressive stress}},
author = {Miglio, Anna and Saniz, R. and Waroquiers, David and Stankovski, Martin and Giantomassi, Matteo and Hautier, Geoffroy and Rignanese, Gian-Marco and Gonze, Xavier},
abstract = {We consider the effects of three different types of applied compressive stress on the structural, electronic and optical properties of rutile SnO2. We use standard density functional theory (DFT) to determine the structural parameters. The effective masses and the electronic band gap, as well as their stress derivatives, are computed within both DFT and many-body perturbation theory (MBPT). The stress derivatives for the SnO2 direct band gap are determined to be 62, 38 and 25 meV/GPa within MBPT for applied hydrostatic, biaxial and uniaxial stress, respectively. Compared to DFT, this is a clear improvement with respect to available experimental data. We also estimate the exciton binding energies and their stress coefficients and compute the absorption spectrum by solving the Bethe�Salpeter equation.},
Keywords = {IMCN/NAPS , CISM:CECI},
language = {Anglais},
journal = {{Optical Materials}},
volume = {38},
number = {1},
pages = {161-166},
issn = {1873-1252},
doi = {10.1016/j.optmat.2014.10.017},
address = {(Netherlands) Amsterdam},
publisher = {Elsevier BV * North-Holland},
year = {2014},
url = {http://hdl.handle.net/2078.1/152436}}

F. Bruneval, J. Crocombette, X. Gonze, B. Dorado, M. Torrent, and F. Jollet, "Consistent treatment of charged systems within periodic boundary conditions: the projector augmented-wave and pseudopotential methods revisited," Physical review. B, Condensed matter and materials physics, vol. 89, iss. 4, p. 045116 1-13, 2014.
[Bibtex]

@article{bruneval2014,
title = {Consistent treatment of charged systems within periodic boundary conditions: The projector augmented-wave and pseudopotential methods revisited},
author = {Bruneval, Fabien and Crocombette, Jean-Paul and Gonze, Xavier and Dorado, Boris and Torrent, Marc and Jollet, Fran�ois},
abstract = {The ab initio calculation of charged defect properties in solids is not straightforward because of the delicate interplay between the long-range Coulomb interaction and the periodic boundary conditions. We derive the projector augmented-wave (PAW) energy and Hamiltonian with special care taken on the potentials from the Coulomb interaction. By explicitly treating the background compensation charge, we find additional terms in the total energy of the charged cells and in the potential. We show that these background terms are needed to accurately reproduce all-electron calculations of the formation energy of a charged defect. In particular, the previous PAW expressions were spuriously sensitive to the pseudization conditions and this artifact is removed by the background term. This PAW derivation also provides insights into the norm-conserving pseudopotential framework.We propose then an alternative definition for the total energy of charged cells and for the Kohn-Sham potential within this framework that better approximates the all-electron results.},
Keywords = {IMCN:NAPS , CISM:CECI},
language = {Anglais},
journal = {{Physical review. B, Condensed matter and materials physics}},
volume = {89},
number = {4},
pages = {045116 1-13},
issn = {1550-235X},
doi = {10.1103/PhysRevB.89.045116},
publisher = {American institute of physics},
year = {2014},
url = {http://hdl.handle.net/2078.1/137947}}

B. Van Troeye, Y. Gillet, S. Poncé, and X. Gonze, "First-principles characterization of the electronic and optical properties of hexagonal LiIO3," Optical Materials, vol. 36, pp. 1494-1501, 2014.
[Bibtex]

@article{vantroeye2014,
title = {{First-principles characterization of the electronic and optical properties of hexagonal LiIO3}},
author = {Van Troeye, Beno�t and Gillet, Yannick and Ponc\'e, Samuel and Gonze, Xavier},
abstract = {Within the density functional theory framework, we investigate the structural, electronic, vibrational, dielectric, piezoelectric and optical properties of hexagonal lithium iodate, including some nonlinear response properties, like the nonlinear dielectric (electronic) susceptibility, the electro-optic tensor and the Raman tensor. Beyond the comparison with available experimental data and the associated analysis, we predict the values of several properties or characteristics of this material, e.g. the phonon frequencies with B symmetry, that are silent in both IR and Raman experiments, the Born effective charges, for which a detailed analysis is performed, Raman susceptibilities and the decomposition of the clamped electro-optic tensor in terms of the different modes. The agreement with available experimental results is reasonable to excellent, depending on the property. The lattice parameters and macroscopic dielectric constants agree to the experimental ones within 2%. The Kohn�Sham electronic bandstructure is predicted, but suffers from the well-known DFT band gap problem. Reflectivity spectra computed with the density functional perturbation theory are in qualitative and quantitative agreements with experiments for incident light along the two main hexagonal axes. The phonon frequencies at the Brillouin zone center are, in average, 5.74% apart from the experimental one. The previous assignment of Raman features is discussed, on the basis of our computed Raman spectra, including relative peak heights. Finally, this study confirms theoretically the large nonlinear coefficients d31 and d33 of 6.6 pm/V and 7.5 pm/V as well as its noteworthy piezoelectric and electro-optic properties that make this material remarkable.},
Keywords = {IMCN:NAPS , CISM:CECI , Density functional theory , Lithium iodate , Cell optimization , Phonon modes , Macroscopic dielectric permittivity , Nonlinear properties},
language = {Anglais},
journal = {{Optical Materials}},
volume = {36},
pages = {1494-1501},
issn = {1873-1252},
doi = {10.1016/j.optmat.2014.04.009},
address = {(Netherlands) Amsterdam},
publisher = {Elsevier BV * North-Holland},
year = {2014},
url = {http://hdl.handle.net/2078.1/144385}}

G. Hautier, A. Miglio, D. Waroquiers, G. Rignanese, and X. Gonze, "How Does Chemistry Influence Electron Effective Mass in Oxides? A High-Throughput Computational Analysis," Chemistry of Materials, vol. 26, iss. 19, pp. 5447-5458, 2014.
[Bibtex]

@article{hautier2014,
title = {{How Does Chemistry Influence Electron Effective Mass in Oxides? A High-Throughput Computational Analysis}},
author = {Hautier, Geoffroy and Miglio, Anna and Waroquiers, David and Rignanese, Gian-Marco and Gonze, Xavier},
abstract = {Many technologies require oxides with high electronic conductivity or mobility (e.g., transparent conducting oxides, oxide photovoltaics, or photocatalysis). Using high-throughput ab initio computing, we screen more than 4000 binary and ternary oxides to identify the compounds with the lowest electron effective mass. We identify 74 promising oxides and suggest a few novel potential n-type transparent conducting oxides combining a large band gap to a low effective mass. Our analysis indicates that it is unlikely to find oxides with electron effective masses significantly lower than the current high-mobility binary oxides (e.g., ZnO and In2O3). Using the large data set, we extract chemical rules leading to low electron effective masses in oxides. Main group elements with (n?1)d10ns0np0 cations in the rows 4 and 5 and groups 12?15 of the periodic table (i.e., Zn2+, Ga3+, Ge4+, Cd2+, In3+, Sn4+, and Sb5+) induce the lowest electron effective masses because of their s orbitals hybridizing adequately with oxygen. More surprisingly, oxides containing 3d transition metals in a low oxidation state (e.g., Mn2+) show also competitive effective masses due to the s character of their conduction band.},
Keywords = {IMCN/NAPS , CISM:CECI},
language = {Anglais},
journal = {{Chemistry of Materials}},
volume = {26},
number = {19},
pages = {5447-5458},
issn = {1520-5002},
doi = {10.1021/cm404079a},
publisher = {American Chemical Society},
year = {2014},
url = {http://hdl.handle.net/2078.1/151806}}

G. Geadah-Antonius, S. Poncé, P. Boulanger, M. Côté, and X. Gonze, "Many-Body Effects on the Zero-Point Renormalization of the Band Structure," Physical Review Letters, vol. 112, iss. 21, p. 215501, 2014.
[Bibtex]

@article{antonius2014,
title = {{Many-Body Effects on the Zero-Point Renormalization of the Band Structure}},
author = {Geadah-Antonius, Gabriel and Ponc\'e, Samuel and Boulanger, Paul and C\^ot\'e, Michel and Gonze, Xavier},
abstract = {We compute the zero-point renormalization (ZPR) of the optical band gap of diamond from many-body perturbation theory using the perturbative G0W0 approximation as well as quasiparticle self-consistent GW. The electron-phonon coupling energies are found to be more than 40% higher than standard density functional theory when many-body effects are included with the frozen-phonon calculations. A similar increase is observed for the zero-point renormalization in GaAs when G0W0 corrections are applied. We show that these many-body corrections are necessary to accurately predict the temperature dependence of the band gap. The frozen-phonon method also allows us to validate the rigid-ion approximation which is always present in density functional perturbation theory.},
Keywords = {IMCN / NAPS , CISM:CECI},
language = {Anglais},
journal = {{Physical Review Letters}},
volume = {112},
number = {21},
pages = {215501},
issn = {1079-7114},
doi = {10.1103/PhysRevLett.112.215501},
publisher = {American Physical Society},
year = {2014},
url = {http://hdl.handle.net/2078.1/153908}}

R. Shaltaf, H. K. Juwhari, B. Hamad, J. Khalifeh, G. Rignanese, and X. Gonze, "Structural, electronic, vibrational, and dielectric properties of LaBGeO5 from first principles," Journal of Applied Physics, vol. 115, iss. 7, p. 74103, 2014.
[Bibtex]

@article{shaltaf2014,
title = {{Structural, electronic, vibrational, and dielectric properties of LaBGeO5 from first principles}},
author = {Shaltaf, Riad and Juwhari, H. K. and Hamad, B. and Khalifeh, J. and Rignanese, Gian-Marco and Gonze, Xavier},
abstract = {Structural, electronic, vibrational, and dielectric properties of LaBGeO5 with the stillwellite structure are determined based on ab initio density functional theory. The theoretically relaxed structure is found to agree well with the existing experimental data with a deviation of less than 0.2%. Both the density of states and the electronic band structure are calculated, showing five distinct groups of valence bands. Furthermore, the Born effective charge, the dielectric permittivity tensors, and the vibrational frequencies at the center of the Brillouin zone are all obtained. Compared to existing model calculations, the vibrational frequencies are found in much better agreement with the published experimental infrared and Raman data, with absolute and relative rms values of 6.04cm??1, and 1.81%, respectively. Consequently, numerical values for both the parallel and perpendicular components of the permittivity tensor are established as 3.55 and 3.71 (10.34 and 12.28), respectively, for the high-(low-)frequency limit.},
Keywords = {CISM:CECI , IMCN/NAPS},
language = {Anglais},
journal = {{Journal of Applied Physics}},
volume = {115},
number = {7},
pages = {074103},
issn = {1089-7550},
doi = {10.1063/1.4866357},
year = {2014},
url = {http://hdl.handle.net/2078.1/140200}}

S. Poncé, G. Geadah-Antonius, Y. Gillet, P. Boulanger, J. Laflamme Janssen, A. Marini, M. Côté, and X. Gonze, "Temperature dependence of electronic eigenenergies in the adiabatic harmonic approximation," Physical review B, vol. 90, iss. 21, 2014.
[Bibtex]

@article{ponce2014,
title = {Temperature dependence of electronic eigenenergies in the adiabatic harmonic approximation},
author = {Ponc\'e, Samuel and Geadah-Antonius, Gabriel and Gillet, Yannick and Boulanger, Paul and Laflamme Janssen, Jonathan and Marini, Andrea and C\^ot\'e, Michel and Gonze, Xavier},
abstract = {The renormalization of electronic eigenenergies due to electron-phonon interactions (temperature dependence and zero-point motion effect) is important in many materials. We address it in the adiabatic harmonic approximation, based on first principles (e.g., density-functional theory), from different points of view: directly from atomic position fluctuations or, alternatively, from Janak�s theorem generalized to the case where the Helmholtz free energy, including the vibrational entropy, is used.We prove their equivalence, based on the usual form of Janak�s theorem and on the dynamical equation. We then also place the Allen-Heine-Cardona (AHC) theory of the renormalization in a first-principles context. The AHC theory relies on the rigid-ion approximation, and naturally leads to a self-energy (Fan) contribution and a Debye-Waller contribution. Such a splitting can also be done for the complete harmonic adiabatic expression, in which the rigid-ion approximation is not required. A numerical study within the density-functional perturbation theory framework allows us to compare the AHC theory with frozen-phonon calculations, with or without the rigid-ion approximation. For the two different numerical approaches without non-rigid-ion terms, the agreement is better than 7 ?eV in the case of diamond, which represent an agreement to five significant digits. The magnitude of the non-rigid-ion terms in this case is also presented, distinguishing specific phonon modes contributions to different electronic eigenenergies.},
Keywords = {IMCN/NAPS , CISM:CECI},
language = {Anglais},
journal = {{Physical review B}},
volume = {90},
number = {21},
issn = {1550-235X},
year = {2014},
url = {http://hdl.handle.net/2078.1/153901}}

S. Poncé, G. Antonius, P. Boulanger, E. Cannuccia, A. Marini, M. Côté, and X. Gonze, "Verification of first-principles codes: Comparison of total energies, phonon frequencies, electron-phonon coupling and zero-point motion correction to the gap between ABINIT and QE/Yambo," Computational Materials Science, vol. 83, pp. 341-348, 2014.
[Bibtex]

@article{ponce2014a,
title = {{Verification of first-principles codes: Comparison of total energies, phonon frequencies, electron-phonon coupling and zero-point motion correction to the gap between ABINIT and QE/Yambo}},
author = {Ponc\'e, Samuel and Antonius, G. and Boulanger, P. and Cannuccia, E. and Marini, A. and C\^ot\'e, M. and Gonze, Xavier},
abstract = {With the ever-increasing sophistication of codes, the verification of the implementation of advanced theoretical formalisms becomes critical. In particular, cross comparison between different codes provides a strong hint in favor of the correctness of the implementations, and a measure of the (hopefully small) possible numerical differences. We lead a rigorous and careful study of the quantities that enter in the calculation of the zero-point motion renormalization of the direct band gap of diamond due to electron� phonon coupling, starting from the total energy, and going through the computation of phonon frequencies and electron�phonon matrix elements. We rely on two independent implementations: Quantum Espresso + Yambo and ABINIT. We provide the order of magnitude of the numerical discrepancies between the codes, that are present for the different quantities: less than 105 Ha per atom on the total energy (5.722 Ha/at), less than 0.07 cm1 on the C; L; X phonon frequencies (555�1330 cm1), less than 0.5% on the square of the electron�phonon matrix elements and less than 4 meV on the zero-point motion renormalization of each eigenenergies (44�264 meV). Within our approximations, the DFT converged direct band gap renormalization in diamond due to the electron�phonon coupling is 0.409 eV (reduction of the band gap).},
Keywords = {IMCN:NAPS , CISM:CECI , Density functional perturbation theory , Electron-phonon coupling , Temperature dependence , Verification , Allen�Heine�Cardona theory , Zero-point motion renormalization , Diamond},
language = {Anglais},
journal = {{Computational Materials Science}},
volume = {83},
pages = {341-348},
issn = {0927-0256},
doi = {10.1016/j.commatsci.2013.11.031},
address = {(Netherlands) Amsterdam},
publisher = {Elsevier BV},
year = {2014},
url = {http://hdl.handle.net/2078.1/135974}}

2013

C. Espejo, T. Rangel, A. H. Romero, X. Gonze, and G. Rignanese, "Band structure tunability in MoS2 under interlayer compression: A DFT and GW study," Physical review B, vol. 87, iss. 24, p. 245114, 2013.
[Bibtex]

@article{espejo2013,
title = {{Band structure tunability in MoS2 under interlayer compression: A DFT and GW study}},
author = {Espejo, C. and Rangel, T. and Romero, A. H. and Gonze, Xavier and Rignanese, Gian-Marco},
abstract = {The electronic band structures of MoS2 monolayer and 2H1 bulk polytype are studied within density-functional theory (DFT) and many-body perturbation theory (GW approximation). Interlayer van der Waals (vdW) interactions, responsible for bulk binding, are calculated with the postprocessing Wannier functions method. From both fat bands and Wannier functions analysis, it is shown that the transition from a direct band gap in the monolayer to an indirect band gap in bilayer or bulk systems is triggered by medium- to short-range electronic interactions between adjacent layers, which arise at the equilibrium interlayer distance determined by the balance between vdW attraction and exchange repulsion. The semiconductor-to-semimetal (S-SM) transition is found from both theoretical methods: around c=10.7 � and c=9.9 � for DFT and GW, respectively. A metallic transition is also observed for the interlayer distance c=9.7 �. Dirac conelike band structures and linear bands near Fermi level are found for shorter c lattice parameter values. The VdW correction to total energy was used to estimate the pressure at which S-SM transition takes place from a fitting to a model equation of state.},
Keywords = {CISM:CECI , IMCN:ARC-NMHO},
language = {Anglais},
journal = {{Physical review B}},
volume = {87},
number = {24},
pages = {245114},
issn = {1550-235X},
doi = {10.1103/PhysRevB.87.245114},
year = {2013},
url = {http://hdl.handle.net/2078.1/130284}}

D. Waroquiers, A. Lherbier, A. Miglio, M. Stankovski, S. Poncé, M. J. T. Oliveira, M. Giantomassi, G. Rignanese, and X. Gonze, "Band widths and gaps from the Tran-Blaha functional: Comparison with many-body perturbation theory," Physical review B - Condensed Matter and Materials Physics, vol. 87, iss. 7, p. 75121, 2013.
[Bibtex]

@article{waroquiers2013,
title = {{Band widths and gaps from the Tran-Blaha functional: Comparison with many-body perturbation theory}},
author = {Waroquiers, David and Lherbier, Aur�lien and Miglio, Anna and Stankovski, Martin and Ponc\'e, Samuel and Oliveira, M.J.T. and Giantomassi, Matteo and Rignanese, Gian-Marco and Gonze, Xavier},
abstract = {For a set of ten crystalline materials (oxides and semiconductors), we compute the electronic band structures using the Tran-Blaha (TB09) functional. The band widths and gaps are compared with those from the local-density approximation (LDA) functional, many-body perturbation theory (MBPT), and experiments. At the density-functional theory (DFT) level, TB09 leads to band gaps in much better agreement with experiments than LDA. However, we observe that it globally underestimates, often strongly, the valence (and conduction) band widths (more than LDA). MBPT corrections are calculated starting from both LDA and TB09 eigenenergies and wave functions. They lead to a much better agreement with experimental data for band widths. The band gaps obtained starting from TB09 are close to those from quasiparticle self-consistent GW calculations, at a much reduced cost. Finally, we explore the possibility to tune one of the semiempirical parameters of the TB09 functional in order to obtain simultaneously better band gaps and widths. We find that these requirements are conflicting. � 2013 American Physical Society.},
Keywords = {IMCN:ARC-NMHO},
language = {Anglais},
journal = {{Physical review B - Condensed Matter and Materials Physics}},
volume = {87},
number = {7},
pages = {075121},
issn = {1098-0121},
doi = {10.1103/PhysRevB.87.075121},
year = {2013},
url = {http://hdl.handle.net/2078.1/128174}}

F. Da Pieve, C. Hogan, D. Lamoen, J. Verbeeck, F. Vanmeert, M. Radepont, M. Cotte, K. Janssens, X. Gonze, and G. Van Tendeloo, "Casting Light on the Darkening of Colors in Historical Paintings," Physical Review Letters, vol. 111, p. 208302 1-5, 2013.
[Bibtex]

@article{dapieve2013,
title = {{Casting Light on the Darkening of Colors in Historical Paintings}},
author = {Da Pieve, Fabiana and Hogan, C. and Lamoen, D. and Verbeeck, J. and Vanmeert, F. and Radepont, M. and Cotte, M. and Janssens, K. and Gonze, Xavier and Van Tendeloo, G.},
abstract = {The degradation of colors in historical paintings affects our cultural heritage in both museums and archeological sites. Despite intensive experimental studies, the origin of darkening of one of the most ancient pigments known to humankind, vermilion (-HgS), remains unexplained. Here, by combining many-body theoretical spectroscopy and high-resolution microscopic x-ray diffraction, we clarify the composition of the damaged paint work and demonstrate possible physicochemical processes, induced by illumination and exposure to humidity and air, that cause photoactivation of the original pigment and the degradation of the secondary minerals. The results suggest a new path for the darkening process which was never considered by previous studies and prompt a critical examination of their findings.},
Keywords = {IMCN:NAPS , CISM:CECI},
language = {Anglais},
journal = {{Physical Review Letters}},
volume = {111},
pages = {208302 1-5},
issn = {1079-7114},
doi = {10.1103/PhysRevLett.111.208302},
address = {(United States) [S.l.]},
publisher = {American Physical Society},
year = {2013},
url = {http://hdl.handle.net/2078.1/136695}}

O. A. Restrepo-Gutiérrez, X. Gonze, P. Bertrand, and A. Delcorte, "Computer simulations of cluster impacts : effect of the atomic masses of the projectile and target," Physical Chemistry Chemical Physics, vol. 15, pp. 7621-7627, 2013.
[Bibtex]

@article{restrepo2013,
title = {Computer simulations of cluster impacts : effect of the atomic masses of the projectile and target},
author = {Restrepo-Guti\'errez, Oscar Antonio and Gonze, Xavier and Bertrand, Patrick and Delcorte, Arnaud},
abstract = {Cluster secondary ion mass spectrometry is now widely used for the characterization of nanostructures. In order to gain a better understanding of the physics of keV cluster bombardment of surfaces and nanoparticles (NPs), the effects of the atomic masses of the projectile and of the target on the energy deposition and induced sputtering have been studied by means of molecular dynamics simulations. 10 keV C60 was used as a model projectile and impacts on both a flat polymer surface and a metal NP were analyzed. In the first case, the mass of the impinging carbon atoms was artificially varied and, in the second case, the mass of the NP atoms was varied. The results can be rationalized on the basis of the different atomic mass ratios of the projectile and target. In general, the emission is at its maximum, when the projectile and target have the same atomic masses. In the case of the supported NP, the emission of the underlying organic material increases as the atomic mass of the NP decreases. However, it is always less than that calculated for the bare organic surface, irrespective of the mass ratio. The results obtained with C60 impacts on the flat polymer are also compared to simulations of C60 and monoatomic Ga impacts on the NP.},
Keywords = {IMCN:NAPS , IMCN:ARC-NMHO , CISM:CECI},
language = {Anglais},
journal = {{Physical Chemistry Chemical Physics}},
volume = {15},
pages = {7621-7627},
issn = {1463-9084},
doi = {10.1039/C3CP50346A},
address = {(United Kingdom) [S.l.]},
publisher = {Royal Society of Chemistry},
year = {2013},
url = {http://hdl.handle.net/2078.1/129183}}

S. Poncé, B. Bertrand, P. F. Smet, D. Poelman, M. Mikami, and X. Gonze, "First-principles and experimental characterization of the electronic and opticalproperties of CaS and CaO," Optical Materials, vol. 35, pp. 1477-1480, 2013.
[Bibtex]

@article{ponce2013,
title = {{First-principles and experimental characterization of the electronic and opticalproperties of CaS and CaO}},
author = {Ponc\'e, Samuel and Bertrand, Bruno and Smet , P.F. and Poelman, D. and Mikami, M. and Gonze, Xavier},
abstract = {Doped alkaline-earth chalcogenides are interesting photoluminescen tmaterials for opto-electronic appli- cations. It is crucial to have an extended knowledge about the undoped bulk CaS and CaO since all the excited state properties of the doped material heavily dep end on it. In this work we investigate the struc- tural parameters, electronic band structures, macroscopic dielectric constants and absorption spectra for CaS and CaO compounds. Their quasi-particle band structure in the GW approximation yields a value of 4.28 eV and 6.02 eV for the indirect theoretical particle gap of CaS and CaO, respectively .The imaginary part of the macroscopic dielectric function e(x) is computed including excitonic effects through the Bethe�Salpeter equ ation. The onset of absorption is within 0.1 eV of the experimental one and the calcu- lated spectrum shows a qualitative agreement with experimen t. Our computed exciton binding energies are 0.27 eV and 0.40 eV for CaS and CaO, respectively.},
Keywords = {IMCN:NAPS , CISM:CECI , Density functional theory , Bethe-Salpeter , Exciton , Calcium chalcogenides , Macroscopic dielectric function , Absorption spectrum},
language = {Anglais},
journal = {{Optical Materials}},
volume = {35},
pages = {1477-1480},
issn = {1873-1252},
doi = {10.1016/j.optmat.2013.03.001},
address = {(Netherlands) Amsterdam},
publisher = {Elsevier BV * North-Holland},
year = {2013},
url = {http://hdl.handle.net/2078.1/127716}}

Y. Gillet, M. Giantomassi, and X. Gonze, "First-principles study of excitonic effects in Raman intensities," Physical review. B, Condensed matter and materials physics, vol. 88, iss. 9, p. 094305/1-9, 2013.
[Bibtex]

@article{gillet2013,
title = {{First-principles study of excitonic effects in Raman intensities}},
author = {Gillet, Yannick and Giantomassi, Matteo and Gonze, Xavier},
abstract = {The ab initio prediction of Raman intensities for bulk solids usually relies on the hypothesis that the frequency of the incident laser light is much smaller than the band gap. However, when the photon frequency is a sizable fraction of the energy gap, or higher, resonance effects appear. In the case of silicon, when excitonic effects are neglected, the response of the solid to light increases by nearly three orders of magnitude in the range of frequencies between the static limit and the gap. When excitonic effects are taken into account, an additional tenfold increase in the intensity is observed.We include these effects using a finite-difference scheme applied on the dielectric function obtained by solving the Bethe-Salpeter equation. Our results for the Raman susceptibility of silicon show stronger agreement with experimental data compared with previous theoretical studies. For the sampling of the Brillouin zone, a double-grid technique is proposed, resulting in a significant reduction in computational effort.},
Keywords = {IMCN:NAPS , CISM:CECI},
language = {Anglais},
journal = {{Physical review. B, Condensed matter and materials physics}},
volume = {88},
number = {9},
pages = {094305/1-9},
issn = {1550-235X},
doi = {10.1103/PhysRevB.88.094305},
address = {(United States) [S.l.]},
publisher = {American institute of physics},
year = {2013},
url = {http://hdl.handle.net/2078.1/135677}}

G. Hautier, A. Miglio, G. Ceder, G. Rignanese, and X. Gonze, "Identification and design principles of low hole effective mass p-type transparent conducting oxides," Nature Communications, vol. 4, p. 2292, 2013.
[Bibtex]

@article{hautier2013,
title = {Identification and design principles of low hole effective mass p-type transparent conducting oxides},
author = {Hautier, Geoffroy and Miglio, Anna and Ceder, Gerbrand and Rignanese, Gian-Marco and Gonze, Xavier},
abstract = {The development of high-performance transparent conducting oxides is critical to many technologies from transparent electronics to solar cells. Whereas n-type transparent con- ducting oxides are present in many devices, their p-type counterparts are not largely com- mercialized, as they exhibit much lower carrier mobilities due to the large hole effective masses of most oxides. Here we conduct a high-throughput computational search on thousands of binary and ternary oxides and identify several highly promising compounds displaying exceptionally low hole effective masses (up to an order of magnitude lower than state-of-the-art p-type transparent conducting oxides), as well as wide band gaps. In addition to the discovery of specific compounds, the chemical rationalization of our findings opens new directions, beyond current Cu-based chemistries, for the design and development of future p-type transparent conducting oxides.},
Keywords = {IMCN/NAPS , CISM:CECI},
language = {Anglais},
journal = {{Nature Communications}},
volume = {4},
pages = {2292},
issn = {2041-1723},
doi = {10.1038/ncomms3292},
year = {2013},
url = {http://hdl.handle.net/2078.1/132912}}

F. Da Pieve, S. Di Matteo, T. Rangel, M. Giantomassi, D. Lamoen, G. Rignanese, and X. Gonze, "Origin of Magnetism and Quasiparticles Properties in Cr-Doped TiO2," Physical Review Letters, vol. 110, iss. 13, p. 136402, 2013.
[Bibtex]

@article{dapieve2013a,
title = {{Origin of Magnetism and Quasiparticles Properties in Cr-Doped TiO2}},
author = {Da Pieve, Fabiana and Di Matteo, S. and Rangel, T. and Giantomassi, Matteo and Lamoen, D. and Rignanese, Gian-Marco and Gonze, Xavier},
Keywords = {CISM:CECI , IMCN/NAPS},
language = {Anglais},
journal = {{Physical Review Letters}},
volume = {110},
number = {13},
pages = {136402},
issn = {1079-7114},
doi = {10.1103/PhysRevLett.110.136402},
year = {2013},
url = {http://hdl.handle.net/2078.1/128665}}

B. Bertrand, S. Poncé, D. Waroquiers, M. Stankovski, M. Giantomassi, M. Mikami, and X. Gonze, "Quasiparticle electronic structure of barium-silicon oxynitrides for white-LED application," Physical review B, vol. 88, iss. 7, p. 075136 1-10, 2013.
[Bibtex]

@article{bertrand2013,
title = {{Quasiparticle electronic structure of barium-silicon oxynitrides for white-LED application}},
author = {Bertrand, Bruno and Ponc\'e, Samuel and Waroquiers, David and Stankovski, Martin and Giantomassi, Matteo and Mikami, M. and Gonze, Xavier},
abstract = {Ba3Si6O12N2:Eu2+ and Ba3Si6O9N4:Eu2+ have strikingly similar atomistic structures, but the former is an efficient green phosphor at working temperature while the latter is a bluish-green phosphor whose luminescence decreases quite fast with temperature. Aiming at the understanding of such different behavior, we compute the quasiparticle electronic band structure of the two hosts, Ba3Si6O12N2 and Ba3Si6O9N4, thanks to many-body perturbation theory in the G0W0 approximation. The gap differs by about 0.43 eV.We analyze the eigenfunctions at the top of the valence band, at the bottom of the conduction band, and also the chemical shifts for the Ba site in the two hosts. The valence bands, directly impacted by the different stoichiometric ratio, are not thought to play a large role in the luminescence. Deceivingly, the dispersive bottom of the conduction band, directly related to luminescent properties, is similar in both compounds. The spatial topology of the probability density of the bottom of the conduction bands differs, as well as the location of the 5d peak, with a much higher energy than the bottom of the conduction band in Ba3Si6O12N2 than in Ba3Si6O9N4. Electromagnetic absorption spectra are also computed for both compounds.},
Keywords = {IMCN:NAPS , CISM:CECI},
language = {Anglais},
journal = {{Physical review B}},
volume = {88},
number = {7},
pages = {075136 1-10},
issn = {1550-235X},
doi = {10.1103/PhysRevB.88.075136},
year = {2013},
url = {http://hdl.handle.net/2078.1/134379}}

M. Oliveira and X. Gonze, "Spin-orbit effects in the bismuth atom and dimer: tight-binding and density functional theorycomparison," The Journal of Physical Chemistry Part B: Condensed Matter, Materials, Surfaces, Interfaces & Biophysical, vol. 46, p. 95101, 2013.
[Bibtex]

@article{oliveira2013,
title = {Spin-orbit effects in the bismuth atom and dimer: tight-binding and density functional theorycomparison},
author = {Oliveira, M. and Gonze, Xavier},
abstract = {We present a simple tight-binding model for the bismuth atom and dimer whose main feature is the inclusion of the spin�orbit coupling in such a way that it allows the study of several electronic properties as a function of the spin�orbit coupling strength. Density functional theory calculations (norm-conserving and full-potential linearized augmented plane wave) are used to obtain the tight-binding parameters and to check the accuracy of the model. The model is then used to show in a straightforward way that, in the case of the bismuth dimer, the inclusion of the spin�orbit coupling produces a set of molecular orbitals that are a mixture of bonding and non-bonding non-relativistic molecular orbitals, thus weakening the molecular bond.},
Keywords = {IMCN:NAPS , IMCN:ARC-NMHO},
language = {Anglais},
journal = {{The Journal of Physical Chemistry Part B: Condensed Matter, Materials, Surfaces, Interfaces & Biophysical}},
volume = {46},
pages = {095101},
issn = {1520-5207},
doi = {10.1088/0953-4075/46/9/095101},
address = {(United States) [S.l.]},
publisher = {American Chemical Society},
year = {2013},
url = {http://hdl.handle.net/2078.1/129184}}