Spin and orbital metallic magnetism in rhombohedral trilayer graphene

Chunli Huang, Tobias M.R. Wolf, Wei Qin, Nemin Wei, Igor V. Blinov, Allan H. MacDonald

Research output: Contribution to journalArticlepeer-review

17 Scopus citations

Abstract

We provide a theoretical interpretation of the metallic broken spin-valley (flavor) symmetry states recently discovered in hole-doped rhombohedral trilayer (ABC) graphene in large electric displacement fields. Our conclusions about the phase diagram and phase transitions combine insights from ABC graphene electronic structure models and mean-field theory, and are guided by the precise magneto-oscillation Fermi-surface-area measurements of recent experiments. We find that the principle of momentum-space condensation plays a key role in determining Fermi-surface reconstructions enabled by broken flavor symmetries when the single-particle bands imply thin annular Fermi seas. The reconstructed Fermi sea consists of one large outer Fermi-surface-enclosed majority-flavor states in reciprocal-space area Amaj and one or more small inner holelike Fermi-surface-enclosed minority-flavor states in Amin that are primarily responsible for nematic order. The competing ground states (valley-Ising, valley-XY, and spin-polarized state) have different Amaj/Amin and exchange energy maximizes this ratio and selects valley-XY nematic metal as the lowest-energy state. We discuss how the nematic pockets explain the observed fractionalization of quantum oscillation frequencies, and propose anisotropic transport and the nonlinear Hall effect as additional observables.

Original languageEnglish
Article numberL121405
JournalPhysical Review B
Volume107
Issue number12
DOIs
StatePublished - Mar 15 2023

Bibliographical note

Publisher Copyright:
© 2023 American Physical Society.

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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