Temperature-dependent competition between dislocation motion and phase transition in CdTe

Abstract

The plastic deformation of semiconductors, a process critical to their mechanical and electronic properties, involves various mechanisms such as dislocation motion and phase transition. Here, we systematically examined the temperature-dependent Peierls stress for 30° and 90° partial dislocations in cadmium telluride (CdTe), using a combination of molecular statics and molecular dynamics simulations with a machine-learning force field, as well as density function theory simulations. Our findings reveal that the 0 K Peierls stresses for these partial dislocations in CdTe are relatively low, ranging from 0.52 GPa to 1.46 GPa, due to its significant ionic bonding characteristics. Notably, in the CdTe system containing either a 30°Cd-core or 90° Te-core partial dislocation, a phase transition from the zinc-blende phase to the $\beta$$\beta$-Sn-like phase is favored over dislocation motion. This suggests a competitive relationship between these two mechanisms, driven by the bonding characteristics within the dislocation core and the relatively low phase transition stress of ∼1.00 GPa. Furthermore, we observed a general trend wherein the Peierls stress for partial dislocations in CdTe exhibits a temperature dependence, which decreases with increasing temperature, becoming lower than the phase transition stress at elevated temperatures. Consequently, the dominant deformation mechanism in CdTe shifts from solid-state phase transition at low temperatures to dislocation motion at high temperatures. This investigation uncovers a compelling interplay between dislocation motion and phase transition in the plastic deformation of CdTe, offering profound insights into the mechanical behavior and electronic performance of CdTe and other II–VI semiconductors.