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HL: Halbleiterphysik

HL 57: Theory of electronic structure

HL 57.6: Vortrag

Freitag, 31. März 2006, 12:15–12:30, BEY 118

GW Calculations Starting from Generalized Kohn-Sham Schemes: Application to InN — •Frank Fuchs¹, Jürgen Furthmüller¹, Friedhelm Bechstedt¹, and Georg Kresse² — ¹Institut für Festkörpertheorie und -optik, FSU-Jena, Max-Wien-Platz 1, 07743 Jena, Germany — ²Institut für Materialphysik and Center for Computational Materials Science, Universität Wien, Austria

The GW approximation of Hedin is arguably the most successful approach for the calculation of quasi-particle (QP) energies. Its accuracy has been proven for a variety of systems. Usually, GW corrections are calculated in a ’one shot’ fashion, calculating G₀ and W₀ from solutions of the Kohn-Sham equations with an exchange-correlation potential in local density or generalized gradient approximation (LDA/GGA). However, this standard approach fails for a number of systems such as InN which share shallow ’semi-core’ electrons and a ’negative gap’ in LDA/GGA. Here we present GW calculations which start from solutions of generalized Kohn-Sham (gKS) equations [1]. Such a procedure yields a positive gap for all the investigated gKS functionals. However, a crucial dependence on the wave-function details is found for the semi-core states. The calculations were performed using a model dielectric function for the GW self-energy. The electron-ion interaction was modeled via the PAW method which provides direct access to the all-electron wave functions.

[1] A. Seidl et al., PRB 53, 3764 (1996)