Proximity-effect-induced Superconducting Gap in Topological Surface States - A Point Contact Spectroscopy Study of NbSe₂/Bi₂Se₃ Superconductor-Topological Insulator Heterostructures.

ABSTRACT: Proximity-effect-induced superconductivity was studied in epitaxial topological insulator Bi₂Se₃ thin films grown on superconducting NbSe₂ single crystals. A point contact spectroscopy (PCS) method was used at low temperatures down to 40 mK. An induced superconducting gap in Bi₂Se₃ was observed in the spectra, which decreased with increasing Bi₂Se₃ layer thickness, consistent with the proximity effect in the bulk states of Bi₂Se₃ induced by NbSe₂. At very low temperatures, an extra point contact feature which may correspond to a second energy gap appeared in the spectrum. For a 16 quintuple layer Bi₂Se₃ on NbSe₂ sample, the bulk state gap value near

SUBMITTER: Dai W 

PROVIDER: S-EPMC5550495 | biostudies-literature | 2017 Aug

REPOSITORIES: biostudies-literature