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This content will become publicly available on June 7, 2019

Title: Superconducting proximity effect in a topological insulator using Fe(Te, Se)

Interest in the superconducting proximity effect has recently been reignited by theoretical predictions that it could be used to achieve topological superconductivity. Low- T c superconductors have predominantly been used in this effort, but small energy scales of ~1 meV have hindered the characterization of the emergent electronic phase, limiting it to extremely low temperatures. In this work, we use molecular beam epitaxy to grow topological insulator Bi 2Te 3 in a range of thicknesses on top of a high- T c superconductor Fe(Te,Se). Using scanning tunneling microscopy and spectroscopy, we detect Δ ind as high as ~3.5 meV, which is the largest reported gap induced by proximity to an s -wave superconductor to date. We find that Δ ind decays with Bi 2Te 3 thickness, but remains finite even after the topological surface states have been formed. Finally, by imaging the scattering and interference of surface state electrons, we provide a microscopic visualization of the fully gapped Bi 2Te 3 surface state due to Cooper pairing. Lastly, our results establish Fe-based high- T c superconductors as a promising new platform for realizing high- T c topological superconductivity.
Authors:
 [1] ;  [1] ;  [1] ;  [1] ;  [2] ;  [2] ;  [2] ;  [1] ;  [1]
  1. Boston College, Chestnut Hill, MA (United States). Dept. of Physics
  2. Brookhaven National Lab. (BNL), Upton, NY (United States)
Publication Date:
Report Number(s):
BNL-207884-2018-JAAM
Journal ID: ISSN 2469-9950; PRBMDO
Grant/Contract Number:
SC0012704; W911NF-17-1-0399; NSF-DMR-1654041; FG02-99ER45747
Type:
Accepted Manuscript
Journal Name:
Physical Review B
Additional Journal Information:
Journal Volume: 97; Journal Issue: 22; Journal ID: ISSN 2469-9950
Publisher:
American Physical Society (APS)
Research Org:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); US Army Research Office (ARO); National Science Foundation (NSF)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY
OSTI Identifier:
1462410
Alternate Identifier(s):
OSTI ID: 1441022