Topological phase and optical properties of bulks and nanolayers of ScNiX (X = Ga and In) half-Heusler compounds

In this paper, topological phase and optical properties of bulks and nanolayers (NLs) of the ScNiX (X = Ga and In) half-Heusler compounds have been studied. The calculations have been done based on the density functional theory in the framework of the Wien2k package. The generalized gradient approximation was used for the exchange-correlation functional. Electronic structures and density of states of the bulks and NLs of the compounds show that, they are non-magnetic and metal. It is found that, the bulks of compounds don't have topological phase, but the NLs of compounds have topological phase. Thus, the NLs of both compounds are topological metals. Important optical properties of these compounds were acquired. The results show that, there is optical anisotropy in the NLs, between the in-plane (x) and out-of-plane (z) directions. The absorptions of the bulks and NLs of the compounds are high in the UV range.