Proximity-effect-induced superconductivity in topological insulator-related material Bi2Se3

TL;DR

This study demonstrates that superconductivity can be induced in the topological insulator Bi2Se3 through proximity effects at a Pb interface, enabling Josephson currents and a gap-like conductance feature.

Contribution

It reveals a novel proximity-induced superconducting state in Bi2Se3 that extends over a large volume, differing from previous interface-confined effects.

Findings

Superconducting state is induced in Bi2Se3 near Pb interface.

A Josephson supercurrent can be carried through Bi2Se3.

A gap-like structure appears in conductance spectra.

Abstract

We have studied the electron transport properties of topological insulator-related material Bi2Se3 near the superconducting Pb-Bi2Se3 interface, and found that a superconducting state is induced over an extended volume in Bi2Se3. This state can carry a Josephson supercurrent, and demonstrates a gap-like 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 Bi2Se3.