First-principles study of structural and electronic properties of group IV arsenides with 3:4 stoichiometry

Abstract

The structural and electronic properties of four group IV arsenides with 3:4 stoichiometry, i.e., C3 As4, Si3 As4, Ge3 As4, and Sn3 As4, were systematically investigated using a first-principles method based on the density functional theory and generalized gradient approximation. It was found that all four arsenides energetically favor the pseudocubic phase which is exceptionally stable compared to other phases. C3 As4 is predicted to be metallic, while Si3 As4, Ge3 As4, and Sn3 As4 are semiconductors. Si3 As4 and Sn3 As4 should have sizable and comparable energy gaps while the band gap of Ge3 As4 may be smaller. In addition, the β and cubic phases of Ge3 As4 and Sn3 As4 become softened under pressure, and the graphitic phase becomes unstable as the group IV element evolves from C to Sn. © 2006 The American Physical Society.