Ab initio study of Cmca phase of Bi50Sn50 ordered alloy

The geometrical structure, energetics and electronic properties of Cmca phase of Bi50Sn50 ordered alloy at 3 GPa were investigated using first-principle method, where two configurations were considered. The optimized structure parameters are consistent with the available experimental results. And it is found that the structure with Bi occupying 8d Wyckoff position is more preferable energetically and mechanically. The mechanical analysis suggests that the structure where Sn occupies 8d Wyckoff position is elastically unstable. For the structures considered, the corresponding total and partial electronic density of states were also discussed.