Effect of Pressure on the Elastic Parameters and Structure of CdS

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 dlnC₁₁dP=3.56, dlnC₃₃dP=3.44, dlnC₁₃dP=10.0, dlnC₄₄dP=-4.22, dlnC₆₆dP=-4.97 (in Mbar^-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.