Magnetism from the Berry ring of fire in rhombohedral graphene.

Oral-In-person

Abstract

Rhombohedral graphene (RG) hosts spin and valley symmetry broken quarter metal phases which exhibit strong orbital magnetism tied to underlying Berry curvature. Berry curvature is not evenly distributed in the trigonally warped bands, rather is concentrated away from the band-edge in an annular structure, dubbed the "Berry ring of fire." The experimentally observed distribution of magnetism within the RG quarter metal is thus tied to the Fermi surface geometry, and may reveal nematic instabilities. We use high resolution nanoSQUID on Tip (nSOT) magnetometry to explore the orbital ferromagnetism in the symmetry broken quarter metal regime of 5 and 13 layer RG, revealing a rich phenomenology including domains, valley meta-stability, and differentiated structure beyond the scope of rigid band Stoner iso-spin ferromagnetism. These results have implications for nematic quarter metal physics and for exotic states, such as chiral superconductivity, known to occur within RG quarter metals.

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Presenters

  • Trevor Arp

    • University of California, Santa Barbara

Authors

  • Trevor Arp

    • University of California, Santa Barbara

  • Owen Sheekey

    • University of California, Santa Barbara

  • Yi Guo

    • University of California, Santa Barbara

  • Evgeny Redekop

    • University of California, Santa Barbara

  • Ben Foutty

  • Canxun Zhang

    • University of California, Santa Barbara

  • Ludwig Holleis

    • University of California, Santa Barbara

  • Youngjoon Choi

    • University of California, Santa Barbara

  • Hari Stoyanov

  • Ysun Choi

  • Martin Huber

    • University of Colorado, Denver

  • Takashi Taniguchi

    • National Institute for Materials Science

  • Kenji Watanabe

    • National Institute for Materials Science

  • Andrea Young

    • University of California, Santa Barbara