Ab initio study of GaN properties using VASP software package

The Vienna Ab-initio Software Package VASP is applied to investigate basic properties of wide band gap semiconductor GaN. For two polytypes 2H- and 3C-GaN the band gap structure calculations are performed. The optimal selection of crystal input data and numerical accuracy dependence on k-mesh are discussed. The results show that calculated band gap is ca 40% less than experimental for both polytypes. Effective masses and densities of states for holes and electrons have been calculated for both polytypes and compared with the experimental results.