Zinc-blende GaN: ab initio calculations

The purpose of this paper is to contribute, on a theoretical basis, an understanding of future wide-gap device concepts and applications based on III–V nitride semiconductors. The electronic properties of zinc-blende structure GaN and their (110), (100) and (111) surfaces are investigated using ab initio calculations based on the full potential linear augmented plane-wave (FPLAPW) method within the large unit cell approach, and on the molecular Gaussian-92 code. Lattice constant, cohesive energy, bulk modulus are obtained from total energy calculations. Light-hole and heavy-hole effective masses along (100), (111) and (110) directions and electron masses at Γ point are extracted from band structure calculations and compared with previous ones based on pseudopotential methods. The hydrostatic pressure dependence of the ΓΓ, ΓX and ΓL energy gaps are also obtained. Comparing our band structure and `molecular clusterʹ calculations, the relaxations of the surfaces are found to be mostly determined by local rehybridization or valence effects and are basically independent of energy band features.