Phases of a phenomenological model of twisted bilayer graphene

ORAL

Abstract

We propose a lattice scale two-band generalized Hubbard model as a caricature of the electronic structure of twisted bilayer graphene. Various possible broken symmetry phases can arise, including a nematic phase (which is a form of orbital ferromagnet) and an orbital-triplet spin-singlet superconducting phase. Concerning the mechanism of superconductivity -- we propose an analogy with superconductivity in alkali-doped C_{60} in which a violation of Hund's first rule plays a central role.

*This work was supported in part by the Department of Energy, Office of Basic Energy Sciences, under contract no. DE-AC02- 76SF00515 at Stanford (JFD, SAK, YS, XQS and CW). YS was also supported by the Zuckerman STEM Leadership Program.

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Presenters

  • Chao Wang

    • Physics Department, Stanford University

Authors

  • John Dodaro

    • Physics Department, Stanford University
    • Stanford University

  • Steven Kivelson

    • Physics Department, Stanford University
    • Stanford University

  • Yoni Schattner

    • Physics Department, Stanford University
    • Stanford Insitute for Material and Energy Science

  • Xiao-Qi Sun

    • Physics Department, Stanford University
    • Stanford University

  • Chao Wang

    • Physics Department, Stanford University