Effect of Pressure on the Elastic Parameters and Structure of CdS

Abstract

The effective elastic constants of CdS have been measured by the ultrasonic pulse-echo method as a function of hydrostatic pressure to 4 kbar. The logarithmic pressure derivatives determined were $\frac{d\mathrm{ln}{C}_{11}}{\mathrm{dP}}=3.56$, $\frac{d\mathrm{ln}{C}_{33}}{\mathrm{dP}}=3.44$, $\frac{d\mathrm{ln}{C}_{13}}{\mathrm{dP}}=10.0$, $\frac{d\mathrm{ln}{C}_{44}}{\mathrm{dP}}=\ensuremath{-}4.22$, $\frac{d\mathrm{ln}{C}_{66}}{\mathrm{dP}}=\ensuremath{-}4.97$ (in ${\mathrm{Mbar}}^{\ensuremath{-}1}$). A continuous-deformation model of the wurtzite-to-rocksalt pressure-induced transformation in CdS is presented. A combination of elastic constants characteristic of this deformation is derived and the transformation discussed in terms of a microscopic shear mechanism based on these results.