First-principles calculations of the band gap and optical properties of germanium sulfide

摘要: There are controversial results among the available experimental data of germanium sulfide band gap, as well between these and theoretical model-based calculations published to date. To elucidate this situation, we performed an ab initio calculation its electronic structure adopting local density generalized gradient approximations for exchange-correlation potential. In addition, were carried out with without inclusion spin-orbit interaction. The main difference our previous is that found several critical points in valence conduction bands compete defining gap. This explains diversity existent results, which also a consequence strong crystal anisotropy. Also, suggest important role $s\text{\ensuremath{-}}\mathrm{Ge}$ states contribution at edge band. Based on structure, discuss core spectra optical properties sulfide. We excellent agreement data. Furthermore, calculated functions $\mathrm{GeS}$ satisfactorily compared against existing they explain origin transitions.