Vibrational characteristics of ZnS phase B1 under high pressure

Abstract

High pressure induces vital characterizations in solid materials making them attractive for variety of applications. This study investigated the effect of high pressure on vibrational properties of ZnS using two different equations of state (EoS); Dodson EoS and Bardeen EoS. Thermal and mechanical characterizations, such as volume compression ratio, bulk modulus, Grüneisen parameter, Debye temperature, and the phonon density of states are considered to study. The volume compression ratio calculated due to the two considered EoSs seems to be equivalent to each other up to 17 Gpa, along with a good agreement with published data to a pressure of around 12 Gpa. The bulk modulus of ZnS is increased from 70 GPa at ambient pressure to around 135 Gpa under high pressure of 17 Gpa. Furthermore, the Grüneisen parameter at atmospheric pressure is 1.2, it is slightly decreasing to reach around 1.03 at the highest applied pressure. The present optimization investigates the phonon frequency spectrum of ZnS at different pressures values of (6, 9 and 12) Gpa. Increasing in the energy of the active modes along with decreasing the number of the exited modes are observed. The last calculation, evaluates high pressure effects on the Debye temperature of the material by using two model formulations in combining with the considered EoSs. It is found that the Debye pressure is considerably boosted from 257 °C to around 300 °C at the pressure of 15 GPa.