Meta-GGA calculation of the electronic structure of group III–V nitrides

Abstract

The ground state electronic structure of wurtzite AlN, GaN, and InN has been calculated using full-relativistic all-electron full-potential linearized-augmented plane-wave method. Several DFT exchange-correlation functionals, including the recently proposed non-empirical meta-generalised gradient approximation (Meta-GGA) have been used. The role played by relativistic effects and meta-GGA functional on the band structures and the density of states is discussed. We find that the meta-GGA improves the accuracy of the structural properties as well as the energies of the semicore d states in both GaN and InN. This new functional slightly outperforms the local density approximation (LDA) and the generalized gradient approximation (GGA) overall as to lattice parameters, bulk modulus, and valence band widths. We find also that the meta-GGA induced modifications of the band structure are significant, but limited to the valence band states, while leaving all other features identical to LDA and GGA calculations. Finally, our results show that GaN and InN present anomalous dependence of the valence band splitting versus pressure. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)