Enhanced superconductivity in Bi2Se3/Nb heterostructures

The superconducting proximity effect in topological insulator and superconductor heterostructures has aroused intensive research interest in the past decade. While many efforts have been made to investigate the induced superconductivity in topological insulators, the exploration of the effect of topological insulators on superconductors is comparatively rare. Here, we report the observation of an enhanced superconductivity in Bi2Se3/Nb heterostructures. The superconducting transition temperature and the critical field of Bi2Se3/Nb heterostructures are higher than those of the pristine Nb thin films. Such enhanced superconductivity is due to the improved superfluid stiffness in Nb thin films by proximity to the metallic Bi2Se3 flakes. Our findings will further advance the understanding of the superconducting proximity effect in the heterostructures.