Structural and electronic properties of InSb1-xBix(x=0, 0.25, 0.5, 0.75, 1)

In this study, the structural properties and electronic band structure of InSb1-xBix (x=0, 0.25, 0.5, 0.75, 1) alloys are investigated using density functional theory utilizing the WIEN2K package. The results related to the structural properties showed that the lattice constant, as a function of x, is in excellent agreement with Vegard's linear rule. Calculations involving the investigation of the band structure using the mBJGGA exchange-correlation potential reveal that InSb is a semiconductor with a small gap , exhibiting a normal band order at the Γ point while InBi is a metal that exhibits a band inversion at the Γ point. By adding Bi to InSb and forming InSb0.75Bi0.25 and InSb0.25Bi0.75 alloys, the normal band order and the gap at the Γ point disappear. This leads to a transition from a narrow band gap semiconductor with normal band order (InSb) to a gapless semiconductor (InSb0.75Bi0.25) and a metal (InSb0.25Bi0.75) with an inverted band order. By replacing half of the Sb atoms with Bi atoms in InSb and creating the InSb0.5Bi0.5 alloy, not only is an inverted band order observed at the Γ point but a band gap is also created and a transition from a conventional semiconductor to a topological semiconductor occurs.