Theoretical Investigation of Pressure-Induced Structural Phase Change and Elastic Behavior of Osmium Silicide

The pressure-induced structural change and elastic properties of OsSi compound were investigated by using the two-body interatomic interaction potential. Therefore, with an interionic potential method, which is extended up to next nearest neighbors, was adopted to establish the structural stability and to estimate the elastic properties of the OsSi compound under different values of pressure. These properties were studied up to a maximum of 10 GPa. Our calculations showed that a structural phase transformation from the NaCl-type (B1) structure (sixfold-coordinated system) to (B2) type structure occurred around 8 GPa. The abrupt discontinuity in volume can be seen in the pressure–volume diagram, which again indicates the first-order nature of structural phase transformation in this compound. Furthermore, the ideal lattice parameter of the unit cell, bulk modulus, and pressure derivative have been determined using the effective interionic interaction potential (EIoIP) for the compound under consideration.