5 results on '"Gonze, X."'
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2. Density-operator theory of orbital magnetic susceptibility in periodic insulators.
- Author
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Gonze, X. and Zwanziger, J. W.
- Subjects
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OPERATOR theory , *MAGNETIC susceptibility , *MAGNETIC fields , *HAMILTONIAN systems , *PERTURBATION theory - Abstract
The theoretical treatment of homogeneous static magnetic fields in periodic systems is challenging, as the corresponding vector potential breaks the translational invariance of the Hamiltonian. Based on density operators and perturbation theory, we propose for insulators a periodic framework for the treatment of magnetic fields up to arbitrary order of perturbation, similar to widely used schemes for electric fields. The second-order term delivers a new, remarkably simple formulation of the macroscopic orbital magnetic susceptibility for periodic insulators. We validate the latter expression using a tight-binding model, analytically from the present theory and numerically from the large-size limit of a finite cluster, with excellent numerical agreement. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
3. ABINIT: First-principles approach to material and nanosystem properties
- Author
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Gonze, X., Amadon, B., Anglade, P.-M., Beuken, J.-M., Bottin, F., Boulanger, P., Bruneval, F., Caliste, D., Caracas, R., Côté, M., Deutsch, T., Genovese, L., Ghosez, Ph., Giantomassi, M., Goedecker, S., Hamann, D.R., Hermet, P., Jollet, F., Jomard, G., and Leroux, S.
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COMPUTER software , *NUMERICAL analysis , *COMPUTER systems , *NANOTECHNOLOGY , *DENSITY functionals , *MANY-body problem , *PERTURBATION theory , *ELECTRONIC structure - Abstract
Abstract: ABINIT [http://www.abinit.org] allows one to study, from first-principles, systems made of electrons and nuclei (e.g. periodic solids, molecules, nanostructures, etc.), on the basis of Density-Functional Theory (DFT) and Many-Body Perturbation Theory. Beyond the computation of the total energy, charge density and electronic structure of such systems, ABINIT also implements many dynamical, dielectric, thermodynamical, mechanical, or electronic properties, at different levels of approximation. The present paper provides an exhaustive account of the capabilities of ABINIT. It should be helpful to scientists that are not familiarized with ABINIT, as well as to already regular users. First, we give a broad overview of ABINIT, including the list of the capabilities and how to access them. Then, we present in more details the recent, advanced, developments of ABINIT, with adequate references to the underlying theory, as well as the relevant input variables, tests and, if available, ABINIT tutorials. Program summary: Program title: ABINIT Catalogue identifier: AEEU_v1_0 Distribution format: tar.gz Journal reference: Comput. Phys. Comm. Programming language: Fortran95, PERL scripts, Python scripts Computer: All systems with a Fortran95 compiler Operating system: All systems with a Fortran95 compiler Has the code been vectorized or parallelized?: Sequential, or parallel with proven speed-up up to one thousand processors. RAM: Ranges from a few Mbytes to several hundred Gbytes, depending on the input file. Classification: 7.3, 7.8 External routines: (all optional) BigDFT [1], ETSF IO [2], libxc [3], NetCDF [4], MPI [5], Wannier90 [6] Nature of problem: This package has the purpose of computing accurately material and nanostructure properties: electronic structure, bond lengths, bond angles, primitive cell size, cohesive energy, dielectric properties, vibrational properties, elastic properties, optical properties, magnetic properties, non-linear couplings, electronic and vibrational lifetimes, etc. Solution method: Software application based on Density-Functional Theory and Many-Body Perturbation Theory, pseudopotentials, with planewaves, Projector-Augmented Waves (PAW) or wavelets as basis functions. Running time: From less than one second for the simplest tests, to several weeks. The vast majority of the >600 provided tests run in less than 30 seconds. References: [1] http://inac.cea.fr/LSim/BigDFT. [2] http://etsf.eu/index.php?page=standardization. [3] http://www.tddft.org/programs/octopus/wiki/index.php/Libxc. [4] http://www.unidata.ucar.edu/software/netcdf. [5] http://en.wikipedia.org/wiki/MessagePassingInterface. [6] http://www.wannier.org. [Copyright &y& Elsevier]
- Published
- 2009
- Full Text
- View/download PDF
4. Many-Body Effects on the Zero-Point Renormalization of the Band Structure.
- Author
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Antonius, G., Poncé, S., Boulanger, P., Côté, M., and Gonze, X.
- Subjects
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RENORMALIZATION group , *OPTICAL rotation , *PHOTONIC band gap structures , *PERTURBATION theory , *ELECTRON-phonon interactions , *QUASIPARTICLES - 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. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
5. G0W0 band gap of ZnO: Effects of plasmon-pole models.
- Author
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Stankovski, M., Antonius, G., Waroquiers, D., Miglio, A., Dixit, H., Sankaran, K., Giantomassi, M., Gonze, X., Côté, M., and Rignanese, G.-M.
- Subjects
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BAND gaps , *PERTURBATION theory , *PLASMONS (Physics) , *DEFORMATIONS (Mechanics) , *ZINC oxide - Abstract
Carefully converged calculations are performed for the band gap of ZnO within many-body perturbation theory (G0W0 approximation). The results obtained using four different well-established plasmon-pole models are compared with those of explicit calculations without such models (the contour-deformation approach). This comparison shows that, surprisingly, plasmon-pole models depending on the f-sum rule gives less precise results. In particular, it confirms that the band gap of ZnO is underestimated in the G0W0 approach as compared to experiment, contrary to the recent claim of Shih et al. [Phys. Rev. Lett. 105, 146401 (2010)]. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
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