Unraveling Convoluted Structural and Electronic Transitions in SnTe at High Pressure*

The longstanding uncertainty in high-pressure structural evolution of SnTe has greatly impeded the understanding of its complex electronic properties. Here we unravel the convoluted high-pressure phase transitions of SnTe using angle-dispersive synchrotron x-ray diffraction combined with first-principles structural search. We identify three coexisting intermediate phases of Pnma, Cmcm, and GeS type structure and establish the corresponding phase boundaries. We further unveil the intricate pressure-driven evolution of the energetics, kinetics and lattice dynamics of SnTe to elucidate its distinct phase-transition mechanisms. Subsequent electronic band calculations reveal pressure-induced metallization, superconductivity and topological phase transition in SnTe. These findings resolve structures and predict intriguing properties of SnTe, which have broad implications for other IV-VI semiconductors that likely harbor similar novel high-pressure phases and properties.