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Title: Tuning superconductivity in twisted bilayer graphene

Abstract

Materials with flat electronic bands often exhibit exotic quantum phenomena owing to strong correlations. An isolated low-energy flat band can be induced in bilayer graphene by simply rotating the layers by 1.1°, resulting in the appearance of gate-tunable superconducting and correlated insulating phases. In this study, we demonstrate that in addition to the twist angle, the interlayer coupling can be varied to precisely tune these phases. We induce superconductivity at a twist angle larger than 1.1°—in which correlated phases are otherwise absent—by varying the interlayer spacing with hydrostatic pressure. Our low-disorder devices reveal details about the superconducting phase diagram and its relationship to the nearby insulator. Our results demonstrate twisted bilayer graphene to be a distinctively tunable platform for exploring correlated states.

Authors:
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Publication Date:
Research Org.:
Energy Frontier Research Centers (EFRC) (United States). Programmable Quantum Materials (Pro-QM); Columbia Univ., New York, NY (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1566722
DOE Contract Number:  
SC0019443
Resource Type:
Journal Article
Journal Name:
Science
Additional Journal Information:
Journal Volume: 363; Journal Issue: 6431; Journal ID: ISSN 0036-8075
Publisher:
AAAS
Country of Publication:
United States
Language:
English
Subject:
optics, defects, charge transport, superconductivity, magnetism and spin physics, mesoscale science, materials and chemistry by design, mesostructured materials, synthesis (novel materials), synthesis (self-assembly)

Citation Formats

Yankowitz, Matthew, Chen, Shaowen, Polshyn, Hryhoriy, Zhang, Yuxuan, Watanabe, K., Taniguchi, T., Graf, David, Young, Andrea F., and Dean, Cory R. Tuning superconductivity in twisted bilayer graphene. United States: N. p., 2019. Web. doi:10.1126/science.aav1910.
Yankowitz, Matthew, Chen, Shaowen, Polshyn, Hryhoriy, Zhang, Yuxuan, Watanabe, K., Taniguchi, T., Graf, David, Young, Andrea F., & Dean, Cory R. Tuning superconductivity in twisted bilayer graphene. United States. doi:10.1126/science.aav1910.
Yankowitz, Matthew, Chen, Shaowen, Polshyn, Hryhoriy, Zhang, Yuxuan, Watanabe, K., Taniguchi, T., Graf, David, Young, Andrea F., and Dean, Cory R. Thu . "Tuning superconductivity in twisted bilayer graphene". United States. doi:10.1126/science.aav1910.
@article{osti_1566722,
title = {Tuning superconductivity in twisted bilayer graphene},
author = {Yankowitz, Matthew and Chen, Shaowen and Polshyn, Hryhoriy and Zhang, Yuxuan and Watanabe, K. and Taniguchi, T. and Graf, David and Young, Andrea F. and Dean, Cory R.},
abstractNote = {Materials with flat electronic bands often exhibit exotic quantum phenomena owing to strong correlations. An isolated low-energy flat band can be induced in bilayer graphene by simply rotating the layers by 1.1°, resulting in the appearance of gate-tunable superconducting and correlated insulating phases. In this study, we demonstrate that in addition to the twist angle, the interlayer coupling can be varied to precisely tune these phases. We induce superconductivity at a twist angle larger than 1.1°—in which correlated phases are otherwise absent—by varying the interlayer spacing with hydrostatic pressure. Our low-disorder devices reveal details about the superconducting phase diagram and its relationship to the nearby insulator. Our results demonstrate twisted bilayer graphene to be a distinctively tunable platform for exploring correlated states.},
doi = {10.1126/science.aav1910},
journal = {Science},
issn = {0036-8075},
number = 6431,
volume = 363,
place = {United States},
year = {2019},
month = {1}
}

Works referenced in this record:

Pairing symmetry in cuprate superconductors
journal, October 2000