Elastic Properties of Semiconducting Crystals belonging to the Diamond, Blende, and Wurtzite Types

When a face-centered crystal is referred to axes bound to a close-packed plane, its elastic moduli possess the C3v type of symmetry. They differ from the elastic moduli in the axes of the cube by a multiple of the quantity C=C11–C12–2C44. The reduced value of C is nearly the same for Ge and the four III–V semiconducting compounds whose elastic moduli have been measured. A comparison between the cells of blende and wurtzite suggests, for crystals of the latter type, a simple relation which appears to be well satisfied in the case of CdS.