Pressure induced structural phase transition and elastic behavior of Y and Sc antimonides

Pressure induced structural aspects of NaCl-type (B1) to CsCl-type (B2) structure in yttrium and scandium antimonides are presented. An effective interionic interaction potential (EIOP) with long-range Coulomb, van der Waals (vdW) interaction and the short-range repulsive interaction upto second-neighbor ions within the Hafemeister and Flygare approach with modified ionic charge is developed. Particular attention is devoted to evaluate the vdW coefficients following the Slater–Kirkwood variational method, as both the ions are polarizable. Our results on vast volume discontinuity in pressure volume phase diagram identifies the structural phase transition from B1 to B2 structure. 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 variations of elastic constants and their combinations with pressure follow a systematic trend identical to that observed in others compounds of NaCl-type structure family and the Born and relative stability criteria is valid in yttrium and scandium antimonides.