The electronic structure and elastic properties of NbSiSb and NbGeSb: A first-principles study

Abstract

A systematic first-principles study on crystal and electronic structure and elastic properties of NbXSb (X = Ge, Si) is carried out using density functional theory (DFT). The results on atomic bonding show that the main bonding is covalent bonds for both NbSiSb and NbGeSb. Both materials show abundant band structures. The calculated bulk band and density of states with and without the spin-orbit coupling effect (SOC) suggest that SOC leads to the band gaps opening around the Fermi level. Further analysis of the slab model with different layers reveals a topologically protected Dirac cone near the Fermi level in NbGeSb. Moreover, the brittleness of NbSiSb is larger than NbGeSb, and the anisotropy of elastic moduli decreases when Si replaces Ge. This work may provide new inspiration and ideas for understanding the behaviour of topological materials.