A COMPARISON OF FORCE-CONSTANTS, MECHANICAL AND THERMAL-PROPERTIES IN HG1-XCDXTE AND HG1-XZNXTE MIXED-CRYSTALS

Interatomic force constants are deduced from a fit of infrared reflectivity data of HgCdTe (MCT) and HgZnTe (MZT) mixed crystals using a basic unit model for the description of vibrational modes of low wave vector. This allows, for the first time, a direct comparison of bond strengths between MCT and MZT. The obtained results are consistent with a slight decrease in bond strength when Cd is substituted for Hg in MCT and an increase when Zn replaces Hg in MZT. These results are visualized through the bulk modulus variations with composition in both mixed crystals and are compared to known results on their thermal properties.