Unusual magnetotransport in twisted bilayer graphene

Joe Finney; Aaron L Sharpe; Eli J Fox; Connie L Hsueh; Daniel E Parker; Matthew Yankowitz; Shaowen Chen; Kenji Watanabe; Takashi Taniguchi; Cory R Dean; Ashvin Vishwanath; M A Kastner; David Goldhaber-Gordon

doi:10.1073/pnas.2118482119

Unusual magnetotransport in twisted bilayer graphene

Proc Natl Acad Sci U S A. 2022 Apr 19;119(16):e2118482119. doi: 10.1073/pnas.2118482119. Epub 2022 Apr 11.

Authors

Joe Finney^{1

2}, Aaron L Sharpe^{2

3}, Eli J Fox^{1

2}, Connie L Hsueh^{2

3}, Daniel E Parker⁴, Matthew Yankowitz^{5

6}, Shaowen Chen^{4

7

8}, Kenji Watanabe⁹, Takashi Taniguchi¹⁰, Cory R Dean⁷, Ashvin Vishwanath⁴, M A Kastner^{1

2

11}, David Goldhaber-Gordon^{1

2}

Affiliations

¹ Department of Physics, Stanford University, Stanford, CA 94305.
² Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA 94025.
³ Department of Applied Physics, Stanford University, Stanford, CA 94305.
⁴ Department of Physics, Harvard University, Cambridge, MA 02138.
⁵ Department of Physics, University of Washington, Seattle, WA 98195.
⁶ Department of Materials Science and Engineering, University of Washington, Seattle, WA 98195.
⁷ Department of Physics, Columbia University, New York, NY 10027.
⁸ Department of Applied Physics and Applied Mathematics, Columbia University, New York, NY 10027.
⁹ Research Center for Functional Materials, National Institute for Materials Science, Tsukuba 305-0044, Japan.
¹⁰ International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba 305-0044, Japan.
¹¹ Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139.

Abstract

SignificanceWhen two sheets of graphene are twisted to the magic angle of 1.1^∘, the resulting flat moiré bands can host exotic correlated electronic states such as superconductivity and ferromagnetism. Here, we show transport properties of a twisted bilayer graphene device at 1.38^∘, far enough above the magic angle that we do not expect exotic correlated states. Instead, we see several unusual behaviors in the device's resistivity upon tuning both charge carrier density and perpendicular magnetic field. We can reproduce these behaviors with a surprisingly simple model based on Hofstadter's butterfly. These results shed light on the underlying properties of twisted bilayer graphene.

Keywords: Hofstadter’s butterfly; anisotropy; twisted bilayer graphene.

Abstract

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