Proximity-effect-induced superconducting phase in the topological insulator Bi[subscript 2]Se[subscript 3]

Abstract

We have studied the electron transport properties of topological insulator-related material Bi[subscript 2]Se[subscript 3] near the superconducting Pb-Bi[subscript 2]Se[subscript 3] interface, and found that a superconducting state is induced over an extended volume in Bi[subscript 2]Se[subscript 3]. This state can carry a Josephson supercurrent, and demonstrates a gaplike structure in the conductance spectra as probed by a normal-metal electrode. The establishment of the gap is not by confining the electrons into a narrow space close to the superconductor-normal metal interface, as previously observed in other systems, but presumably via electron-electron attractive interaction in Bi[subscript 2]Se[subscript 3].