Hybrid functional study of band structures of GaAs1−xNxand GaSb1−xNxalloys

Abstract

Band structures of GaAs${}_{1\ensuremath{-}x}$N${}_{x}$ and GaSb${}_{1\ensuremath{-}x}$N${}_{x}$ alloys are studied in the framework of the density functional theory within the hybrid functional scheme (HSE06). We find that the scheme gives a clear improvement over the traditional (semi)local functionals in describing, in a qualitative agreement with experiments, the bowing of electron energy band gap in GaAs${}_{1\ensuremath{-}x}$N${}_{x}$ alloys. In the case of GaSb${}_{1\ensuremath{-}x}$N${}_{x}$ alloys, the hybrid functional used makes the study of band structures possible ab initio without any empirical parameter fitting. We explain the trends in the band gap reductions in the two materials that result mainly from the positions of the nitrogen-induced states with respect to the bottoms of the bulk conduction bands.