Multiband superconductivity in strongly hybridized 1 T ' - WTe 2 / NbSe 2 heterostructures
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- Nanyang Technological University (Singapore)
- Indian Institute of Technology (IIT), Madras (India)
- University of Tokyo, Kashiwa (Japan)
- Agency for Science Technology and Research (A*STAR) (Singapore)
- Nanyang Technological University (Singapore); Agency for Science Technology and Research (A*STAR) (Singapore)
- Northeastern University, Boston, MA (United States)
- Institute of Physics, Academia Sinica, Taipei (Taiwan)
- Nanyang Technological University (Singapore); Monash University, Melbourne, VIC (Australia)
The interplay of topology and superconductivity has become a subject of intense research in condensed-matter physics for the pursuit of topologically nontrivial forms of superconducting pairing. An intrinsically normal-conducting material can inherit superconductivity via electrical contact to a parent superconductor via the proximity effect, usually understood as Andreev reflection at the interface between the distinct electronic structures of two separate conductors. However, at high interface transparency, strong coupling inevitably leads to changes in the band structure, locally, owing to hybridization of electronic states. Here, we investigate such strongly proximity-coupled heterostructures of monolayer $1T$' - $$\mathrm{WTe_2}$$ grown on NbSe2 by van der Waals epitaxy. The superconducting local density of states, resolved in scanning tunneling spectroscopy down to 500 mK, reflects a hybrid electronic structure well described by a multiband framework based on the McMillan equations which captures the multiband superconductivity inherent to the NbSe2 substrate and that is induced by proximity to $$\mathrm{WTe_2}$$ self-consistently. Our material-specific tight-binding model captures the hybridized heterostructure quantitatively and confirms that strong interlayer hopping gives rise to a semimetallic density of states in the two-dimensional $$\mathrm{WTe_2}$$ bulk, even for nominally band-insulating crystals. The model further accurately predicts the measured order parameter Δ ≅ 0.6 meV induced in the $$\mathrm{WTe_2}$$ monolayer bulk, stable beyond a 2 T magnetic field. So we believe that our detailed multiband analysis of the hybrid electronic structure provides a useful tool for sensitive spatial mapping of induced order parameters in proximitized atomically thin topological materials.
- Research Organization:
- Northeastern Univ., Boston, MA (United States); Univ. of California, Oakland, CA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES); National Research Foundation of Korea (NRF); Singapore Ministry of Education; Japan Society for the Promotion of Science (JSPS); Agency for Science, Technology and Research (A*STAR); Ministry of Science and Technology (MOST)
- Grant/Contract Number:
- SC0019275; AC02-05CH11231; 16H02109; 18K19013; 19H00859; A1685b0005; MOST 109-2112-M-001-014-MY3; NRF-NRFF2017-11
- OSTI ID:
- 1979727
- Alternate ID(s):
- OSTI ID: 1856452
- Journal Information:
- Physical Review. B, Vol. 105, Issue 9; ISSN 2469-9950
- Publisher:
- American Physical Society (APS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
band gap
density of states
edge states
local density of states
methods in superconductivity
multiband superconductivity
proximity effect
superconducting gap
superconductivity
topological insulators
topological materials
topological phases of matter