Itinerant spin and valley ferromagnetism in rhombohedral trilayer graphene (Part II)

ORAL

Abstract

Under an applied electrical displacement field, rhombohedral (ABC-stacked) trilayer graphene is a semiconductor with an unusually flat band minimum. Here we show that the resulting high density of states near the band edges leads to an instability towards ferromagnetic states in which one or more of the spin and valley symmetries are broken. In this second of two presentations, we will focus on the phenomenology of the observed magnetism within the combined spin- and valley isospin. Using low magnet field quantum oscillations and tilted field magnetocapacitance, we classify the competing ferromagnetic states by their spin- and valley symmetry breaking. Remarkably, measurements of similarly fabricated devices in which the trilayer graphene is aligned to a hexagonal boron nitride substrate reveal a pattern of ferromagnetic phase transitions that is only weakly perturbed relative to the superlattice free case. Our measurements show that ABC trilayer graphene hosts rare high mobility, two dimensional “half” and “quarter” metal states, and provides insight into the origin of magnetism in moire systems.

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Presenters

  • Haoxin Zhou

    • Department of Physics, University of California, Santa Barbara

Authors

  • Haoxin Zhou

    • Department of Physics, University of California, Santa Barbara

  • Tian Xie

    • Department of Physics, University of California, Santa Barbara

  • James Ehrets

    • Department of Physics, University of California, Santa Barbara
    • Harvard University

  • Eric M Spanton

    • California NanoSystems Institute, University of California, Santa Barbara

  • Takashi Taniguchi

    • National Institute for Materials Science, Japan
    • National Institute for Materials Science
    • Department of Chemical Engineering, Kyoto University
    • National Institute for Materials Science, Tsukuba, Ibaraki, Japan
    • International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
    • Materials, NIMS
    • International Center for Materials Anorthite, National Institute for Materials Science, Ibaraki, Japan
    • Kyoto University

  • Kenji Watanabe

    • National Institute for Materials Science
    • National Institute for Materials Science, Japan
    • National Institure for Materials Science
    • Advanced Materials Laboratory, National Institute for Materials Science
    • NIMS
    • National Institute of Materials Science
    • National Institute for Materials Science (NIMS)
    • Research Center for Functional Materials, National Institute for Materials Science
    • National Institute for Materials Science,1-1 Namiki
    • National Institute of Material Science
    • National Institute for Materials Science, Tsukuba, Japan
    • Research Center for Functional Materials, NIMS
    • National Institute of Materials Science, Tsukuba, Japan
    • National Institude for Materials Science
    • National Institute for Materials Science, Tsukuba, Ibaraki, Japan
    • Research Center for Functional Materials, National Institute for Materials Science, Tsukuba 305-0044, Japan
    • International Center for Materials Nanoarchitectonics, National Institute for Materials
    • NIMS - Japan
    • National Institute for Materials Science ,Japan
    • National Institute for Materials Science, Tsukuba, 305-0044, Ibaraki, Japan
    • National Institute for Material Science
    • National Institute for Material Science, 1-1 Namiki, Tsukuba 305-0044, Japan
    • National Institute for Material Science Japan
    • NIMS Tsukuba
    • National Institute for Materials Science, Research Center for Functional Materials, Japan
    • Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
    • National Institute for Materials Science: Namiki, Tsukuba, Ibaraki, JP
    • National Institue for Material Science
    • National Institute for Materials Science,1-1 Namiki, Tsukuba, 305-0044, Japan
    • Materials, NIMS
    • Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan, Research Center for Functional Materials, National In
    • Research Center for Functional Materials, Japan
    • International Center for Materials Nanoarchitectonics, National Institute for Materials Science
    • International Center for Materials nanoarchtectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan
    • NIMS Suguba
    • NIMS, Tsukuba, Japan
    • National Institute for Materials Science, Namiki 1-1, Tsukuba, 305-0044, Ibaraki, Japan
    • National institute of material science
    • Advanced Materials Laboratory, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan
    • Advanced Materials Laboratory, NIMS
    • Research Center for Functional Materials, National Institute for Materials Science, Ibaraki, Japan
    • National Institute for Materials Science, Research Center for Functional Materials
    • National Institute of Material Science, Japan
    • Tsukuba, National Institute for Materials Science

  • Maksym Serbyn

    • Institute of Science and Technology, Austria
    • Institute of Science and Technology Austria

  • Areg Ghazaryan

    • Institute of Science and Technology, Austria

  • Erez Berg

    • Weizmann Institute of Science
    • Department of Condensed Matter Physics, Weizmann Institute of Science

  • Andrea Young

    • Department of Physics, University of California, Santa Barbara
    • University of California, Santa Barbara