Magnetic anisotropy in twisted bilayer graphene and ABC-trilayer graphene aligned with hexagonal boron nitride

ORAL

Abstract

We and others have previously reported ferromagnetism in both twisted bilayer graphene (tBLG) and ABC-trilayer graphene aligned with hexagonal boron nitride (hBN) evinced by a large (or even quantized) hysteretic anomalous Hall effect. These systems are composed entirely of non-magnetic elements; the magnetism arises from the strong electronic correlations of these moiré systems. Here, we report that when tilting the sample in an external magnetic field, the ferromagnetism of the two systems is highly anisotropic. In tBLG, the magnetism switches at a threshold out-of-plane component of the magnetic field down to tilt angles of about 5°. Because spin–orbit coupling is weak in graphene, such anisotropy is unlikely to come from spin but rather favors theories in which the ferromagnetism is orbital. The situation is less clear in the ABC-trilayer graphene moiré. The magnetic state at -2.3 electrons per moiré unit cell exhibits similar behavior to tBLG, switching at a threshold out-of-plane field. However, the other magnetic state observed at -1 electrons per moiré unit cell does not exhibit such a threshold, suggesting that either the spin of the electron is playing a role or the in-plane field is directly coupling to the orbital degree of freedom.

*Device fabrication, measurements, and analysis were supported by the U.S.Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engi-neering Division, under Contract DE-AC02-76SF00515. Infrastructure and cryostat supportwere funded in part by the Gordon and Betty Moore Foundation through Grant GBMF3429.Part of this work was performed at the Stanford Nano Shared Facilities (SNSF), supported bythe National Science Foundation under award ECCS-1542152.A. S. acknowledges supportfrom an ARCS Foundation Fellowship, a Ford Foundation Predoctoral Fellowship, and a Na-tional Science Foundation Graduate Research Fellowship. E. F. acknowledges support froman ARCS Foundation Fellowship. K.W. and T.T. acknowledge support from the Elemen-tal Strategy Initiative conducted by the MEXT, Japan, Grant Number JPMXP0112101001,JSPS KAKENHI Grant Number JP20H00354 and the CREST (JPMJCR15F3), JSTA. A portion of this work was supported by Sandia Academic Alliance program. Sandia

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Publication: Aaron L. Sharpe, Eli J. Fox, Arthur W. Barnard, Joe Finney, Kenji Watanabe, Takashi Taniguchi, Marc A. Kastner, and David Goldhaber-Gordon
Nano Letters 2021 21 (10), 4299-4304
DOI: 10.1021/acs.nanolett.1c00696

Guorui Chen*, Aaron L. Sharpe*, Eli J. Fox*, Shaoxin Wang, Bosai Lyu, Lili Jiang, Hongyuan Li, Kenji Watanabe, Takashi Taniguchi, Michael F. Crommie, Marc A. Kastner, Zhiwen Shi, David Goldhaber-Gordon, Yuanbo Zhang, and Feng Wang
arXiv:2012.10075

Presenters

  • Aaron L Sharpe

    • Sandia National Laboratories

Authors

  • Aaron L Sharpe

    • Sandia National Laboratories

  • Guorui Chen

    • University of California, Berkeley

  • Eli J Fox

    • Stanford Univ

  • Arthur W Barnard

    • University of Washington

  • Joe Finney

    • Stanford Univ

  • Shaoxin Wang

    • University of California, Berkeley

  • Bosai Lyu

    • Shanghai Jiao Tong University,

  • Lili Jiang

    • University of California, Berkeley

  • Hongyuan Li

    • University of California, Berkeley
    • Lawrence Berkeley National Laboratory

  • Kenji Watanabe

    • National Institute for Materials Science, Tsukuba, Japan
    • National Institute for Materials Science
    • NIMS
    • Research Center for Functional Materials, National Institute for Materials Science, Tsukuba, Ibaraki 305-0044, Japan
    • Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan.
    • Research Center for Functional Materials, National Institute for Materials Science
    • Advanced, Materials Laboratory, NIMS
    • 3 National Institute for Materials Science, Tsukuba, Japan
    • National Institute for Materials Science; 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
    • National Institute of Materials Science, Tsukuba, Japan
    • National Institute of Materials Science
    • Advanced Materials Laboratory, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan
    • National Institute for Materials Science (Japan)
    • National Institute for Materials Science, Japan
    • Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
    • Research Center for Functional Materials
    • Research Center for Functional Materials, National Institute for Materials Science, Tsukuba, Japan
    • Research Center for Functional Materials, National Institute for Materials Science, Japan
    • Research Center for Functional Materials, National Institute for Materials Science, 1-1Namiki, Tsukuba 305-0044, Japan
    • National Institute for Material Science, Japan
    • National Institute for Material Science
    • National Institute of Material Sciences, Japan
    • NIMS, Tsukuba
    • 2National Institute for Materials Science, Namiki 1-1, Ibaraki 305-0044, Japan.
    • National Institute of Materials Science, Tsukuba, Ibaraki 305-0044, Japan
    • National Institute for Materials Science Japan
    • NIMS, Japan
    • nims
    • National Institute for Materials Science, Research Center for Functional Materials, Japan
    • National Institute for Materials Science Tsukuba
    • National Institute for Materials Science, 1-1 Namiki
    • National Institute for Materials Science of Japan
    • National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
    • NIMS - National Institute for Material Science, Japan
    • Research Center for Functional Materials, National Institute for Material Science, Tsukuba, Ibaraki, 305-0044, Japan.
    • National Institute for Material Science, Tsukuba
    • National Institute for Materials Science, Tsukuba, Ibaraki 305-0044, Japan
    • National Institute for Materials Science (NIMS)
    • National Institute for Materials Science, Research Center for Functional Materials
    • Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
    • National Institute of Material Science
    • Kyoto Univ
    • National Institute for Materials Science,1-1 Namiki, Tsukuba, 305-0044, Japan

  • Takashi Taniguchi

    • National Institute for Materials Science, Tsukuba, Japan
    • National Institute for Materials Science
    • NIMS
    • Kyoto Univ
    • International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Ibaraki 305-0044, Japan.
    • 3 National Institute for Materials Science, Tsukuba, Japan
    • National Institute for Materials Science; 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
    • National Institute of Materials Science, Tsukuba, Japan
    • National Institute of Materials Science
    • Advanced Materials Laboratory, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan
    • National Institute for Materials Science (Japan)
    • International Center for Materials Nanoarchitectonics, National Institute for Materials Science
    • International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
    • Kyoto University
    • International Center for Materials Nanoarchitectonics
    • International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Japan
    • International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Japan
    • International Center for Materials Nanoarchitectonics, National Institute for MaterialsScience, 1-1 Namiki, Tsukuba 305-0044, Japan
    • National Institute for Material Science, Japan
    • National Institute for Material Science
    • National Institute of Material Sciences, Japan
    • NIMS, Tsukuba
    • 2National Institute for Materials Science, Namiki 1-1, Ibaraki 305-0044, Japan.
    • National Institute of Materials Science, Tsukuba, Ibaraki 305-0044, Japan
    • National Institute for Materials Science, Japan
    • International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science, 1-1 Namiki Tsukuba, Ibaraki 305-0044, Japan.
    • NIMS, Japan
    • National Institute for Materials Science (NIMS)
    • NIMS. Japan
    • International Center for Material Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Japan
    • International Center for Material Nanoarchitectonics, National Institute for Materials Science
    • National Institute for Materials Science Tsukuba
    • National Institute for Materials Science, 1-1 Namiki
    • National Institute for Materials Science of Japan
    • National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
    • NIMS - National Institute for Material Science, Japan
    • International Center for Materials Nanoarchitectonics, National Institute for Material Science, Tsukuba, Ibaraki 305-0044, Japan.
    • National Institute for Material Science, Tsukuba
    • National Institute for Materials Science, International Center for Materials Nanoarchitectonics
    • International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
    • National Institute of Material Science
    • National Institute for Materials Science,1-1 Namiki, Tsukuba, 305-0044, Japan

  • Michael F Crommie

    • University of California, Berkeley

  • Marc A Kastner

    • Stanford Univ
    • Stanford University

  • Zhiwen Shi

    • Shanghai Jiao Tong Univ

  • Yuanbo Zhang

    • Fudan Univ

  • David Goldhaber-Gordon

    • Stanford University
    • Stanford Univ

  • feng wang

    • University of California, Berkeley