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Discovery of a Cooper-pair density wave state in a transition-metal dichalcogenide

Cornell Affiliated Author(s)

Author

X. Liu
Y.X. Chong
R. Sharma
J.C.S. Davis

Abstract

Pair density wave (PDW) states are defined by a spatially modulating superconductive order parameter. To search for such states in transition-metal dichalcogenides (TMDs), we used high-speed atomicresolution scanned Josephson-tunneling microscopy. We detected a PDW state whose electron-pair density and energy gap modulate spatially at the wave vectors of the preexisting charge density wave (CDW) state. The PDW couples linearly to both the s-wave superconductor and the CDW and exhibits commensurate domains with discommensuration phase slips at the boundaries, conforming those of the lattice-locked commensurate CDW. Nevertheless, we found a global dF ≡ ± 2p/3 phase difference between the PDW and CDW states, possibly owing to the Cooper-pair wave function orbital content. Our findings presage pervasive PDW physics in the many other TMDs that sustain both CDW and superconducting states. © 2021 American Association for the Advancement of Science. All rights reserved.

Date Published

Journal

Science

Volume

372

Issue

6549

Number of Pages

1447-1452,

URL

https://www.scopus.com/inward/record.uri?eid=2-s2.0-85108587475&doi=10.1126%2fscience.abd4607&partnerID=40&md5=6695d5c47160b0f65299527497d7b407

DOI

10.1126/science.abd4607

Group (Lab)

J.C. Seamus Davis Group

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