Structural Phase Transitions and Metallized Phenomena in Arsenic Telluride under High Pressure

In this study, first-principle calculations, in situ angle-dispersive X-ray diffraction, and in situ electrical resistance measurements were performed on arsenic telluride (As₂Te₃) under high pressure. Structural phase transitions and metallized phenomena were observed from the calculated and experimental results. Upon compression, α-As₂Te₃ transforms into phases α′ and αa″ at ∼5.09 and ∼13.2 GPa, respectively, with two isostructural phase transitions. From 13.2 GPa, As₂Te₃ starts to transform into phase γ, with one first-order monoclinic to monoclinic crystal structural phase transition. According to the first-principle calculations and electrical resistance measurements, the structural phase transitions in the compression process induce the transformation from an insulator (phase α) across a semimetal (phase α′) into a metal (phases α″ and γ). The evolution of the structure and transport property upon compression on As₂Te₃ is helpful for understanding the properties of other A₂B₃-type compounds under high pressure.