Pressure induced structural phase transition of XC (X = Si, Ge, Sn)

An effective interionic interaction potential (EIOP) is developed to investigate the pressure induced phase transitions from ZnS-type (B3) to NaCl-type (B1) in XC [X = Si, Ge, and Sn] compounds. The long range Coulomb, van der Waals (vdW) interaction and the short-range repulsive interaction up to second-neighbor ions within the Hafemeister and Flygare approach with modified ionic charge are properly incorporated in the EIOP. The vdW coefficients are computed following the Slater-Kirkwood variational method, as both the ions are polarizable. The estimated value of the phase transition pressure (Pt) and the magnitude of the discontinuity in volume at the transition pressure are consistent as compared to the reported data. The vast volume discontinuity in pressure volume phase diagram identifies the structural phase transition from B3 to B1 structure.