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Coupled Spin and Orbital Magnetism in ABC Trilayer Graphene

ORAL

Abstract

ABC trilayer graphene under an applied perpendicular electric field hosts a van Hove singularity that can be accessed by field-effect doping, where a variety of spin and valley symmetry breaking ferromagnetic phases have been observed. Among these are a ‘quarter metal’ phase, where quantum oscillations show the existence of a single Fermi surface [1]. Using both tilted-magnetic field transport, capacitance, and nanoSQUID on Tip (nSOT) microscopy, I will show that the quarter metal regime actually hosts two distinct phases, separated by a first order phase transition and distinguished by different orbital and spin magnetic moments. Surprisingly, the orbital magnetic moment of one of these phases can be tuned by an in-plane magnetic field, implying that the orbital motion is coupled to the electron spin despite the lack of atomic spin orbit coupling. I will discuss our results in the context of novel mechanisms for emergent spin orbit coupling arising from the interplay of Coulomb interactions, spin textures, and orbital magnetism [2].
[1] Zhou, H., Xie, T., Ghazaryan, A. et al. Nature 598, 429–433 (2021).

[2] Dong, Z., Levitov, L., arXiv:2208.02051.

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Presenters

  • Trevor B Arp

    University of California, Riverside, University of California, Santa Barbara

Authors

  • Trevor B Arp

    University of California, Riverside, University of California, Santa Barbara

  • Charles L Tschirhart

    UC Santa Barbara, University of California, Santa Barbara

  • Owen I Sheekey

    University of California, Santa Barbara

  • Evgeny Redekop

    University of California, Santa Barbara

  • Haoxin Zhou

    Department of Applied Physics and Material Science, California Institute of Technology; Department of Physics, University of California at Santa Barbara, California Institute of Technology

  • Martin E Huber

    University of Colorado, Denver

  • Andrea Young

    University of California, Santa Barbara