Critical stress of Hg1−xCdxTe solid solutions

Abstract

The motion of dislocations in crystals is known to be impeded by the addition of isovalent impurities at concentrations of a few percent. By treating the Hg1−xCdxTe alloy as resulting from the addition of Cd impurities into the HgTe lattice, the critical resolved shear stress for solid-solution hardening in this material is calculated at room temperature as a function of Cd composition x. In this solid solution model, the critical stress is derived from the elastic size interaction between the Cd solute atoms and the edge dislocations in a HgTe solvent. The predicted dependence of the critical stress on x at room temperature compares favorably with experimental results for the lower yield stress. Estimates of the critical stress at temperatures up to 440 °C are also made at selected compositions by using the relation for the temperature and strain rate dependence of the lower yield stress.