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Title: Proximity-induced superconducting gap in the quantum spin Hall edge state of monolayer WTe2

Abstract

The quantum spin Hall insulator is characterized by a bandgap in the two-dimensional (2D) interior and helical 1D edge states1,2,3. Inducing superconductivity in the helical edge state results in a 1D topological superconductor, a highly sought-after state of matter at the core of many proposals for topological quantum computing4. In the present study, we report the coexistence of superconductivity and the quantum spin Hall edge state in a van der Waals heterostructure, by placing a monolayer of 1T'-WTe2, a quantum spin Hall insulator1,2,3, on a van der Waals superconductor, NbSe2. Using scanning tunnelling microscopy and spectroscopy (STM/STS), we demonstrate that the WTe2 monolayer exhibits a proximity-induced superconducting gap due to the underlying superconductor and that the spectroscopic features of the quantum spin Hall edge state remain intact. Taken together, these observations provide conclusive evidence for proximity-induced superconductivity in the quantum spin Hall edge state in WTe2, a crucial step towards realizing 1D topological superconductivity and Majorana bound states in this van der Waals material platform.

Authors:
 [1];  [1];  [1]; ORCiD logo [1];  [2]; ORCiD logo [3];  [1]; ORCiD logo [1]
  1. Carnegie Mellon Univ., Pittsburgh, PA (United States)
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Univ. of Tennessee, Knoxville, TN (United States)
  3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES)
OSTI Identifier:
1649055
Grant/Contract Number:  
AC05-00OR22725
Resource Type:
Accepted Manuscript
Journal Name:
Nature Physics
Additional Journal Information:
Journal Volume: 16; Journal Issue: 5; Journal ID: ISSN 1745-2473
Publisher:
Nature Publishing Group (NPG)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY

Citation Formats

Lüpke, Felix, Waters, Dacen, de la Barrera, Sergio C., Widom, Michael, Mandrus, David G., Yan, Jiaqiang, Feenstra, Randall M., and Hunt, Benjamin M.. Proximity-induced superconducting gap in the quantum spin Hall edge state of monolayer WTe2. United States: N. p., 2020. Web. https://doi.org/10.1038/s41567-020-0816-x.
Lüpke, Felix, Waters, Dacen, de la Barrera, Sergio C., Widom, Michael, Mandrus, David G., Yan, Jiaqiang, Feenstra, Randall M., & Hunt, Benjamin M.. Proximity-induced superconducting gap in the quantum spin Hall edge state of monolayer WTe2. United States. https://doi.org/10.1038/s41567-020-0816-x
Lüpke, Felix, Waters, Dacen, de la Barrera, Sergio C., Widom, Michael, Mandrus, David G., Yan, Jiaqiang, Feenstra, Randall M., and Hunt, Benjamin M.. Mon . "Proximity-induced superconducting gap in the quantum spin Hall edge state of monolayer WTe2". United States. https://doi.org/10.1038/s41567-020-0816-x. https://www.osti.gov/servlets/purl/1649055.
@article{osti_1649055,
title = {Proximity-induced superconducting gap in the quantum spin Hall edge state of monolayer WTe2},
author = {Lüpke, Felix and Waters, Dacen and de la Barrera, Sergio C. and Widom, Michael and Mandrus, David G. and Yan, Jiaqiang and Feenstra, Randall M. and Hunt, Benjamin M.},
abstractNote = {The quantum spin Hall insulator is characterized by a bandgap in the two-dimensional (2D) interior and helical 1D edge states1,2,3. Inducing superconductivity in the helical edge state results in a 1D topological superconductor, a highly sought-after state of matter at the core of many proposals for topological quantum computing4. In the present study, we report the coexistence of superconductivity and the quantum spin Hall edge state in a van der Waals heterostructure, by placing a monolayer of 1T'-WTe2, a quantum spin Hall insulator1,2,3, on a van der Waals superconductor, NbSe2. Using scanning tunnelling microscopy and spectroscopy (STM/STS), we demonstrate that the WTe2 monolayer exhibits a proximity-induced superconducting gap due to the underlying superconductor and that the spectroscopic features of the quantum spin Hall edge state remain intact. Taken together, these observations provide conclusive evidence for proximity-induced superconductivity in the quantum spin Hall edge state in WTe2, a crucial step towards realizing 1D topological superconductivity and Majorana bound states in this van der Waals material platform.},
doi = {10.1038/s41567-020-0816-x},
journal = {Nature Physics},
number = 5,
volume = 16,
place = {United States},
year = {2020},
month = {3}
}

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