Pressure-Induced Superconductivity and Phase Transitions in Thermoelectric Material (Bi, Sb)₂Te₃

Bi_xSb_2-xTe₃is a thermoelectric material with a high room-temperature figure of merit, which can be further enhanced through the application of pressure. Recently, we discovered pressure-induced superconductivity up to ~9 K in this system, and the variation in its superconducting transition temperature with pressure indicates possible phase transitions. Systematic X-ray diffraction measurements conducted at room temperature and pressures up to ~50 GPa reveal two distinct structural phase transitions. Our experimental results also suggest possible topological electronic transitions induced by pressure. In addition, our theoretical calculations have helped us verify and shed light on the structural and electronic phase transitions driven by pressure, as well as the underlying mechanisms responsible for the emergence of superconductivity in this system.