First order structural phase transition in strontium chalcogenides at high pressure

Two body potential model, which consists of long-range Coulombic interactions, van der Waals (vdW) interaction, and short-range overlap repulsive interaction effective up to second neighbour ions, has been used to explorer the structural and elastic properties of SrX (X = O, S, Se and Te). The van der Waals coefficients, different hardness and range parameters for both the phases have been incorporated to achieve most accurate results. It is found that there is a good agreement between calculated results and available experimental results on phase transition pressure and volume collapse.

► B1 (NaCl structure) to B2 (CsCl structure) phase transition properties of strontium chalcogenides. ► Phase transition pressure, cohesive energy and equilibrium separation are calculated. ► The hardness parameter (ρ) and second-order elastic constants (SOECs) have been computed.