Proximity-Induced High-Temperature Superconductivity in a Topological Insulator

New topological phases of matter have been proposed to exist at the surface of some materials with spin-orbit coupling called topological insulators. Among the different exotic features of topological insulators, the interface between a topological insulator and a superconductor is of great interest. It is predicted that combining these two materials would lead to the emergence of Majorana fermion excitations which enable several applications in spintronics and quantum computing. Towards this goal, we have investigated Bi$_{2}$Sr$_{2}$CaCu$_{2}$O$_{8+\delta }$(Bi-2212)- Bi$_{2}$Se$_{3}$ interface junctions made by a new mechanical-bonding technique. Current vs. voltage and differential conductance measurements have been performed in various temperatures ranging from room temperature to 5K. Several anomalies were observed in the Andreev spectra including a zero bias conductance peak appearing below the critical temperature of the superconductor Bi-2212 (85K), a reduced gap in Bi-2212 as well as the intrinsic gap of Bi-2212. These features suggest the induction of high-temperature superconductivity in the Bi$_{2}$Se$_{3}$ due to proximity to Bi-2212.