Superconductivity in the Doped Topological Insulator CuxBi2Se3 under High Pressure

We report a high-pressure single crystal study of the topological superconductor CuxBi2Se3. Resistivity measurements under pressure show superconductivity is depressed smoothly. At the same time the metallic behavior is gradually lost. The upper-critical field data B-c2(T) under pressure collapse onto a universal curve. The absence of Pauli limiting and the comparison of B-c2(T) to a polar-state function point to spin-triplet superconductivity, but an anisotropic spin-singlet state cannot be discarded completely.