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

Abstract

We have studied the electron transport properties of topological insulator-related material Bi 2Se 3 near the superconducting Pb-Bi 2Se 3 interface, and found that a superconducting state is induced over an extended volume in Bi 2Se 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 2Se 3. © 2012 American Physical Society.