Regensburg 2007 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 43: Theory of electronic structure
HL 43.3: Vortrag
Donnerstag, 29. März 2007, 14:30–14:45, H14
GW Calculations Starting from Generalized Kohn-Sham Schemes — •Frank Fuchs1, Jürgen Furthmüller1, Friedhelm Bechstedt1, Maxim Shishkin2, and Georg Kresse2 — 1Institut für Festkörpertheorie und -optik, Friedrich-Schiller-Universität 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 in extended systems. Its accuracy has been proven for a variety of systems. Usually, the QP eigenvalues are calculated in a perturbative approach, starting from solutions of the Kohn-Sham equations with an exchange-correlation (XC) potential in local density or generalized gradient approximation (LDA/GGA). However, this standard approach fails for a number of systems such as InN or ZnO with shallow ’semi-core’ electrons and a much too small or even ’negative gap’ in LDA/GGA. Here we present G0W0 calculations for various materials which start from solutions of the generalized Kohn-Sham (gKS) equations for the screened exchange (sX), HSE03, PBE0 and HF model of exchange and correlation. The calculations are performed within the framework of the full potential PAW method. The GW calculations, with various gKS solution as input, are found to yield a positive gap and d-band positions close to the experimental values for all the functionals investigated here. Furthermore, with exception of HF the resulting gaps are almost the same for all the gKS functionals chosen as starting point.