Superconducting pairing of topological surface states in bismuth selenide films on niobium.

ABSTRACT: A topological insulator film coupled to a simple isotropic s-wave superconductor substrate can foster helical pairing of the Dirac fermions associated with the topological surface states. Experimental realization of such a system is exceedingly difficult, however using a novel "flip-chip" technique, we have prepared single-crystalline Bi₂Se₃ films with predetermined thicknesses in terms of quintuple layers (QLs) on top of Nb substrates fresh from in situ cleavage. Our angle-resolved photoemission spectroscopy (ARPES) measurements of the film surface disclose superconducting gaps and coherence peaks of similar magnitude for both the topological surface states and bulk states. The ARPES spectral map as a function of temperature and film thickness up to 10 QLs reveals ke

SUBMITTER: Flototto D 

PROVIDER: S-EPMC5922797 | biostudies-literature | 2018 Apr

REPOSITORIES: biostudies-literature