Global phase diagram of charge-neutral graphene in the quantum Hall regime for generic interactions

Suman Jyoti De, Ankur Das, Sumathi Rao, Ribhu K. Kaul, Ganpathy Murthy

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

Monolayer graphene at charge neutrality in a quantizing magnetic field is a quantum Hall ferromagnet. Due to the spin and valley (near) degeneracies, there is a plethora of possible ground states. Previous theoretical work, based on a stringent ultra-short-range assumption on the symmetry-allowed interactions, predicts a phase diagram with distinct regions of spin-polarized, canted antiferromagnetic, intervalley coherent, and charge density wave order. While early experiments suggested that the system was in the canted antiferromagnetic phase at a perpendicular field, recent scanning tunneling studies universally find Kekulé bond order, and sometimes also charge density wave order. Recently, it was found that if one relaxes the stringent assumption mentioned above a phase with coexisting canted antiferromagnetic and Kekulé order exists in the region of the phase diagram believed to correspond to real samples. In this paper, starting from the continuum limit appropriate for experiments, we present the complete phase diagram of ν=0 graphene in the Hartree-Fock approximation, using generic symmetry-allowed interactions, assuming translation-invariant ground states up to an intervalley coherence. Allowing for a sublattice potential (valley Zeeman coupling), we find numerous phases with different types of coexisting order. We conclude with a discussion of the physical signatures of the various states.

Original languageEnglish
Article number125422
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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