ISSN:
0020-7608
Keywords:
Computational Chemistry and Molecular Modeling
;
Atomic, Molecular and Optical Physics
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
It is well established that the local density approximation (LDA), which is used in a large majority of all solid state band structure studies, severely underestimates band gaps in nonmetals. Here we describe an extension to semiconductors of the local density theory for quasiparticle self-energies. In contrast to the standard Kohn-Sham procedure' that applies rigorously only to ground state properties, this is a theory for the single-particle-like excitations of semiconductors. This approach includes the energy dependence within a local-density-dependent self-energy that is evaluated in the GW-approximation of Hedin. The essential feature is the incorporation of the semiconducting gap into the screening of the Coulomb interaction, which results in an increased energy dependence of the exchange-correlation hole. The resulting theory gives results for silicon and diamond bandgaps and valence bandwidths that are typically within 5% of the experimental value. Similarly good results are obtained for the zincblende IV-IV compound SiC and III-V compound GaP. Results for the anomalous heavier semiconductors Ge and GaAs, for which LDA gives very small to vanishing gaps, will also be discussed.
Additional Material:
4 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/qua.560300728
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