Pressure-induced electronic topological transition and superconductivity in topological insulator Bi2Te2.1Se0.9

Abstract

Great attention has been drawn to topological superconductivity due to its potential application in topological quantum computing. Meanwhile, pressure is regarded as a powerful tool for tuning electronic structure and even inducing superconductivity in topological insulators. As a well-defined topological insulator, Bi2Te2.1Se0.9 can be a suitable candidate to search for topological superconductivity and study its intrinsic property. In this paper, we report the occurrence of superconductivity and electronic topological transition (ETT) in Bi2Te2.1Se0.9 with applied pressure. Superconductivity can be observed at 2.4 GPa with the Tconset around 6.6 K in Bi2Te2.1Se0.9 by resistance measurement, and the corresponding structure resolved by X-ray diffraction and Raman experiments doesn't change below the pressure of 8.4 GPa. Moreover, at about 3.0 GPa, the abnormal changes of c/a as well as the full width at half maximum (FWHM) of mode indicate the occurrence of electronic topological transition (ETT). These results indicate that superconductivity can be realized in doped topological insulator Bi2Te2.1Se0.9 in the low-pressure rhombohedral phase