Correlation-driven super Van Hove singularity in slow graphene

ORAL

Abstract

High-order Van Hove singularities (VHSs) provide a novel mechanism for driving strong electron correlation effects in materials such as the super-metallic state. We show how such VHSs emerge in the paradigmatic family of slow graphenes to produce the excitonic insulator (EI) state. Our systematic analysis reveals a crossover from a weak to a strong electron-correlation regime, which is triggered when velocity of the Dirac carriers is reduced through a renormalization of their bandwidth. The resulting flattening of the edges of the conduction and valence bands yields QΓ = (0, 0) and QM = (π, 0) excitons and produces correlation-driven high-order VHSs with power-law divergences in the density-of-states. Our study indicates that a variety of 2D materials beyond the twisted bilayer graphene would provide viable single-phase material platforms for exploring the physics of high-order VHSs and how these VHSs drive exciting correlation-driven phenomena in quantum matter.

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Presenters

  • Baokai Wang

    • Department of Physics, Northeastern University
    • Northeastern University
    • Department of Physics, Northeastern University, USA

Authors

  • Baokai Wang

    • Department of Physics, Northeastern University
    • Northeastern University
    • Department of Physics, Northeastern University, USA

  • Bahadur Singh

    • Department of Condensed Matter Physics and Materials Science, Tata Institute of Fundamental Research
    • Condensed Matter Physics and Materials Science, Tata Institute of Fundamental Research
    • Department of Condensed Matter Physics and Material Science, Tata Institute of Fundamental Research
    • Tata Institute of Fundamental Research
    • Tata Institute for Fundamental Research
    • DCMPMS, Tata Institute of Fundamental Research, India
    • Condensed Matter Physics and Material Science, Tata Institute of Fundamental Research
    • Department of Condensed Matter Physics & Materials Science, Tata Institute of Fundamental Research

  • Hsin Lin

    • Institute of Physics, Academia Sinica
    • Academia Sinica
    • Institute of Physics, Academia Sinica, Taipei
    • Institute of Physics, Academia Sinica, Taiwan
    • Physics, Academia Sinica

  • Robert Markiewicz

    • Northeastern University
    • NU
    • Northeastern U

  • Arun Bansil

    • Department of Physics, Northeastern University
    • Northeastern University
    • NU
    • Department of Physics, Northeastern University, USA