Superconductivity in bulk polycrystalline metastable phases of Sb2Te3 and Bi2Te3 quenched after high-pressure–high-temperature treatment

Abstract

We synthesized bulk polycrystalline samples of metastable phases of Sb2Te3 and Bi2Te3 topological insulators by rapid quenching after a high-pressure–high-temperature treatment at P=3.7–7.7GPa; T=873K and found superconducting transitions with TConset=2K and 6K, respectively. A low critical current value of about 2mA in the metastable Sb2Te3 phase and an absence of the detectable heat capacity effect at the superconducting transition indicated a low-dimensional character of superconductivity. A zero-field magnetic susceptibility cusp and linear positive magnetoresistance indicate a topological insulator state.