High pressure phase transformation and elastic behaviour of ZnX semiconducting compound

Abstract

An effective interionic interaction potential to investigate the pressure induced phase transitions from zinc blende (<i style="">B</i>3) to rock salt (<i style="">B</i>1) structure and anharmonic properties in ZnX [<i style="">X</i> = Se, S, Te] semiconductors has been presented. The elastic constants, including the long range Coulomb, Van der Waals (<i style="">v</i>d<i style="">W</i>) interaction and the short-range repulsive interaction of up to second-neighbour ions within the Hafemeister and Flugare approach, are derived as a first step. Both of the ions are polarizable, therefore the Slater-Kirkwood variational method is employed to estimate the <i style="">v</i>d<i style="">W</i> coefficients. It is inferred that <i style="">v</i>d<i style="">W</i> interaction is effective in obtaining the thermodynamical parameters such as the Debye temperature, Gruneisen parameter, thermal expansion coefficient and the compressibility. The major volume discontinuity in the pressure-volume phase diagram representing the structural phase transition from zinc blende to rock salt structure, is consistent as those revealed from earlier reports. We find that short-range <i style="">v</i>d<i style="">W</i> attraction, long-range Coulomb repulsion, and short-range overlap repulsion in ZnX will contribute effectively to the mechanical properties and show similar results as those revealed from experiments.