We have investigated the conductance spectra of Sn-Bi${}_2$Se${}_3$ interface junctions down to 250 mK and in different magnetic fields. A number of conductance anomalies were observed below the superconducting transition temperature of Sn, including a small gap that is different from that of Sn, and a zero-bias conductance peak that increases at lower temperatures. We discussed the possible origins of the smaller gap and the zero-bias conductance peak. These phenomena support the idea that a proximity-effect-induced chiral superconducting phase is formed at the interface between the superconducting Sn and the strong spin-orbit coupling material Bi${}_2$Se${}_3$.

• Received 20 February 2012

DOI:https://doi.org/10.1103/PhysRevB.85.104508