Deviatoric stress-induced quasi-reconstructive phase transition in ZnTe

Abstract

Understanding phase evolutions and the underlying mechanism under external stimuli is of fundamental importance for novel material discovery. Herein, combining angular dispersive X-ray diffraction and first-principles pathway sampling, we found that the ZnTe alloy undergoes a quasi-reconstructive transition to a metastable rocksalt phase under deviatoric stress. The rocksalt ZnTe has reconstructed chemical bonds and dendrite crystal morphology. It also suffers more severe thermodynamic hysteresis compared with the same experiments under hydrostatic pressure. However, the phase transition towards the rock-salt phase is still described by relatively small atomic displacements and is slightly first order; thus, it is neither fully displacive nor fully reconstructive. The quasi-reconstructive transition in ZnTe narrows its electronic bandgap and may provide insights into the semiconductor–metal transition in II–VI alloys in general.