Influence of exchange and correlation on structural and electronic properties of AlN, GaN, and InN polytypes

Abstract

Results for structural and elastic properties of wurtzite and zinc-blende group-III nitrides are calculated using the recently developed AM05 exchange-correlation (XC) functional. They are compared to calculations based on the local-density approximation or the generalized-gradient approximation. We find that AM05 provides a better agreement with experimental results. The atomic geometries are used to compute the quasiparticle band structures within Hedin's $GW$ approximation, based on an initial electronic structure calculated using the HSE hybrid XC functional. Important band parameters such as gap energies, crystal-field splittings, spin-orbit coupling constants, and momentum matrix elements are derived. The less precisely known hole masses of InN and the anisotropic spin-orbit constants for wurtzite are predicted. The wave-vector-induced spin-orbit splittings of the valence and conduction bands are discussed.