The Coexistence of Superconductivity and Topological Order in the Bi 2 Se 3 Thin Films

Abstract

All Set for Majoranas When put in the proximity of a superconductor, topological insulators (TIs) are expected to support Majorana fermions, exotic particles that are their own antiparticles. For this to be realized, the interface between the TI and superconductor layers has to be atomically sharp but electronically transparent. Wang et al. (p. 52 , published online 15 March) fabricated this heterostructure by growing a film of the TI material Bi 2 Se 3 on the superconductor NbSe 2 covered with a Bi bilayer. Scanning tunneling spectroscopy revealed a superconducting gap on the TI surface of the heterostructure with varying thickness of the Bi 2 Se 3 film. This coexistence of superconductivity and topological order should now allow observation of exotic phenomena such as Majorana fermions.