Pressure Induced Structural Phase Transition and Elastic Properties of Lutetium Chalcogenides (LuX, X: S, Se and Te)

Abstract

We have investigated, the cohesive energies, pressure-volume relationship, phase transition pressure (P_t) and elastic constants for lutetium chalcogenides (LuX, X: S, Se, Te), using an interionic potential theory with modified ionic charge which includes Coulomb screening effect due to f-electrons.  These compounds undergo structural phase transition from NaCl (B₁) to CsCl (B₂) structure at high pressure (ranges from 10 to 60 GPa).  The B₁ (NaCl) phase is found to be lower in energy than the B₂ (CsCl) phase and more stable at zero pressure.

Keywords: Rare earth chalcogenides; high pressure; elastic properties; equations-of-state;  phase transition.