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Title: Bi-2212/1T-TaS 2 Van der Waals junctions: Interplay of proximity induced high-T c superconductivity and CDW order

Understanding the coexistence, competition and/or cooperation between superconductivity and charge density waves (CDWs) in the transition metal dichalcogenides (TMDs) is an elusive goal which, when realized, promises to reveal fundamental information on this important class of materials. Here in this paper, we use four-terminal current-voltage measurements to study the Van der Waals interface between freshly exfoliated flakes of the high-T c superconductor, Bi-2212, and the CDW-dominated TMD layered material, 1T-TaS 2. For highly transparent barriers, there is a pronounced Andreev reflection feature providing evidence for proximity-induced high-Tc superconductivity in 1T-TaS 2 with a surprisingly large energy gap (~20 meV) equal to half that of intrinsic Bi-2212 (~40 meV). Our systematic study using conductance spectroscopy of junctions with different transparencies also reveals the presence of two separate boson modes, each associated with a “dip-hump” structure. Finally, we infer that the proximityinduced high-T c superconductivity in the 1T-TaS 2 is driven by coupling to the metastable metallic phase coexisting within the Mott commensurate CDW (CCDW) phase and associated with a concomitant change of the CCDW order parameter in the interfacial region.
Authors:
ORCiD logo [1] ;  [1] ;  [1] ; ORCiD logo [1]
  1. Univ. of Florida, Gainesville, FL (United States). Dept. of Physics
Publication Date:
Grant/Contract Number:
FG02-86ER45268; DMR–1305783
Type:
Accepted Manuscript
Journal Name:
Scientific Reports
Additional Journal Information:
Journal Volume: 7; Journal Issue: 1; Journal ID: ISSN 2045-2322
Publisher:
Nature Publishing Group
Research Org:
Univ. of Florida, Gainesville, FL (United States)
Sponsoring Org:
USDOE; National Science Foundation (NSF)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; Surfaces, interfaces and thin films; Electronic properties and materials; Superconducting properties and materials
OSTI Identifier:
1424730