Exact-exchange-based quasiparticle calculations
- Department of Physics, Ohio State University, Columbus, Ohio 43210 (United States)
- Department of Physics, University of Illinois at Urbana-Champaign, Illinois 61801 (United States)
- Lehrstuhl fuer Theoretische Chemie, Technische Universitaet Muenchen, D-85748 Garching, (Germany)
One-particle wave functions and energies from Kohn-Sham calculations with the exact local Kohn-Sham exchange and the local density approximation (LDA) correlation potential [EXX(c)] are used as input for quasiparticle calculations in the GW approximation (GWA) for eight semiconductors. Quasiparticle corrections to EXX(c) band gaps are small when EXX(c) band gaps are close to experiment. In the case of diamond, quasiparticle calculations are essential to remedy a 0.7 eV underestimate of the experimental band gap within EXX(c). The accuracy of EXX(c)-based GWA calculations for the determination of band gaps is as good as the accuracy of LDA-based GWA calculations. For the lowest valence band width a qualitatively different behavior is observed for medium- and wide-gap materials. The valence band width of medium- (wide-) gap materials is reduced (increased) in EXX(c) compared to the LDA. Quasiparticle corrections lead to a further reduction (increase). As a consequence, EXX(c)-based quasiparticle calculations give valence band widths that are generally 1-2 eV smaller (larger) than experiment for medium- (wide-) gap materials. (c) 2000 The American Physical Society.
- OSTI ID:
- 20217698
- Journal Information:
- Physical Review. B, Condensed Matter and Materials Physics, Vol. 62, Issue 11; Other Information: PBD: 15 Sep 2000; ISSN 1098-0121
- Country of Publication:
- United States
- Language:
- English
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