Superconductivity and critical fields of tellurium single crystal under high pressure

Tellurium (Te) is one of the $p$-orbital chalcogens, which shows attractive physical properties at ambient pressure. Here, we systematically investigate both structural and electronic evolution of Te single crystal under high pressure up to 40 GPa. The pressure dependence of the experimental Raman spectrum reveals the occurrence of multiple phase transitions, which is consistent with high-pressure synchrotron x-ray diffraction measurements. The appearance of superconductivity in high-pressure phase of Te is accompanied by structural phase transitions. The high-pressure phases of Te reveal a nonmonotonic evolution of superconducting temperature ${T}_{c}$ with notably different upper critical fields. The theoretical calculations demonstrate that the pressure dependence of the density of states agrees well with the variation of ${T}_{c}$. Our results provide a systematic phase diagram for the pressure-induced superconductivity of Te.