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

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 = 3.7-7.7 GPa; T = 873 K and found superconducting transitions with T-C(onset) = 2 K and 6 K, respectively. A low critical current value of about 2 mA 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. (C) 2015 Elsevier B.V. All rights reserved.