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HL: Halbleiterphysik
HL 57: Theory of electronic structure
HL 57.6: Talk
Friday, March 31, 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)