Superconducting properties of indium-doped topological crystalline insulator SnTe

Abstract

We report on the superconducting properties of indium-doped SnTe. SnTe has recently been explored as a topological crystalline insulator. Single crystals of Sn0.5In0.5Te have been synthesized by a modified Bridgman method. Resistivity measurement performed in the range 1.6–300 K shows a metallic normal state with onset of superconducting transition at . Bulk superconductivity has also been confirmed by DC magnetization, AC susceptibility and rf penetration depth measurements. Zero-temperature upper critical field, lower critical field, coherence length, and penetration depth are estimated to be 1.6 T, 1 mT, 143.5 Å and 853 nm, respectively. The temperature dependence of the low-temperature penetration depth indicates S-wave fully gapped characteristics with BCS (Bardeen-Cooper-Schrieffer) gap . Hall and Seebeck coefficient measurements confirm the dominance of hole conduction with possible phonon-drag effects around . Resistive transition studied under applied magnetic field shows thermally activated flux flow behaviour.