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HL: Fachverband Halbleiterphysik

HL 44: Poster Session I

HL 44.25: Poster

Dienstag, 15. März 2011, 18:00–21:00, P3

Band Parameters of (Al, Ga, In)N Polytypes from Different XC Functionals — •Luiz Cláudio de Carvalho, André Schleife, Frank Fuchs, and Friedhelm Bechstedt — Institut für Festköpertheorie und -optik, Friedrich-Schiller-Universität, Max-Wien-Platz 1, 07743 Jena, Germany

Actually a detailed knowledge of the band parameters of the group-III nitrides is necessary to interpret experimental data and understand theoretical results. The most successful theoretical approach is the Density Functional Theory (DFT), but its accuracy depends on the exchange-correlation (XC) functional. Different XC functionals yield slightly varying results for the structural and electronic properties. However, this effect is less important in comparison to the drastic changes of the electronic band structures by solving the quasiparticle (QP) equation. In this work we present and discuss the qualitative and quantitative influence of the XC functionals LDA, GGA, and AM05 induced by structural changes on the band parameters of the AlN, GaN and InN mononitrides. DFT as implemented in VASP code is used to calculate the structural and elastic properties of zinc-blende and wurtzite polytypes. The QP band structures including the XC self-energy within Hedin's GW approximation are obtained taking almost self-consistency into account using HSE03 hybrid XC functional as a starting point. The gap energies, crystal-fields splittings, momentum matrix elements, effective masses and spin-orbit coupling are computed from the QP band structures. We compare our results with experimental values reported in the literature.