Berlin 2008 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 31: Poster II
HL 31.2: Poster
Dienstag, 26. Februar 2008, 16:30–19:00, Poster D
Indium-oxide polymorphs from first principles: Quasiparticle electronic states — •Frank Fuchs and Friedhelm Bechstedt — Institut für Festkörpertheorie und -optik and European Theoretical Spectroscopy Facility (ETSF), Friedrich-Schiller-Universität, Max-Wien-Platz 1, 07743 Jena, Germany
The electronic structure of In2O3 polymorphs is calculated from first-principles using density functional theory (DFT) and many-body perturbation theory (MBPT). DFT calculations with a local exchange-correlation (XC) functional give the relaxed atomic coordinates of the two stable polymorphs. Their electronic structure, i.e., the band structure, and density of states are studied within MBPT. The quasiparticle equation is solved in two steps. As the zeroth approximation for the XC self-energy the non-local potential resulting from a HSE03 hybrid functional is used. In the sense of a self-consistent procedure G0W0 quasiparticle corrections are computed on top. The calculated direct quasiparticle gaps at Γ amount to 3.3 eV (rhombohedral) and 3.1 eV (cubic). The rhombohedral polymorph is found to exhibit a near degeneracy of the valence-band maxima at the Γ point and on the Γ-L line, while the valence band maximum of the cubic polymorph lies close to Γ. This partially contrasts the results of a recent LDA+U study [1]. The results for gaps, d-band positions, density of states, and optical properties are compared with available experimental data.
[1] P. Erhart et al., Phys. Rev. B 75, 153205 (2007).