Large Pauli Limit Violation and Reentrant Superconductivity in Magic-Angle Twisted Trilayer Graphene
Name
2103.12083.pdf
Description
Submitted version
Size
2.89 MB
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Adobe PDF
Checksum (MD5)
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Author(s)
Cao, Yuan
Park, Jeong Min
Watanabe, Kenji
Taniguchi, Takashi
Jarillo-Herrero, Pablo
Alternative Title
Pauli-limit violation and re-entrant superconductivity in moiré graphene
Date Issued
2021
Journal
Nature
Publisher
Springer Science and Business Media LLC
Citation
Cao, Yuan, Park, Jeong Min, Watanabe, Kenji, Taniguchi, Takashi and Jarillo-Herrero, Pablo. 2021. "Large Pauli Limit Violation and Reentrant Superconductivity in Magic-Angle Twisted Trilayer Graphene." Nature, 595 (7868).
Version
Original manuscript
Abstract
Moiré quantum matter has emerged as a materials platform in which correlated and topological phases can be explored with unprecedented control. Among them, magic-angle systems constructed from two or three layers of graphene have shown robust superconducting phases with unconventional characteristics1-5. However, direct evidence of unconventional pairing remains to be experimentally demonstrated. Here we show that magic-angle twisted trilayer graphene exhibits superconductivity up to in-plane magnetic fields in excess of 10 T, which represents a large (2-3 times) violation of the Pauli limit for conventional spin-singlet superconductors6,7. This is an unexpected observation for a system that is not predicted to have strong spin-orbit coupling. The Pauli-limit violation is observed over the entire superconducting phase, which indicates that it is not related to a possible pseudogap phase with large superconducting amplitude pairing. Notably, we observe re-entrant superconductivity at large magnetic fields, which is present over a narrower range of carrier densities and displacement fields. These findings suggest that the superconductivity in magic-angle twisted trilayer graphene is likely to be driven by a mechanism that results in non-spin-singlet Cooper pairs, and that the external magnetic field can cause transitions between phases with potentially different order parameters. Our results demonstrate the richness of moiré superconductivity and could lead to the design of next-generation exotic quantum matter.
MIT Department
Massachusetts Institute of Technology. Department of Physics
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Creative Commons Attribution-Noncommercial-Share Alike
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DOI of Published Version
https://doi.org/10.1038/S41586-021-03685-Y
