Substrate Doping Effect and Unusually Large Angle van Hove Singularity Evolution in Twisted Bi- and Multilayer Graphene

ORAL

Abstract

Graphene has demonstrated great potential in new-generation electronic applications due to its unique electronic properties such as large carrier Fermi velocity, ultrahigh carrier mobility, and high material stability. Interestingly, the electronic structures can be further engineered in multilayer graphene by the introduction of a twist angle between different layers to create van Hove singularities (vHSs) at adjustable binding energy. In this work, using angle-resolved photoemission spectroscopy with sub-micrometer spatial resolution, the band structures and their evolution are systematically studied with twist angle in bilayer and trilayer graphene sheets. A doping effect is directly observed in graphene multilayer system as well as vHSs in bilayer graphene over a wide range of twist angles (from 5° to 31°) with wide tunable energy range over 2 eV. In addition, the formation of multiple vHSs (at different binding energies) is also observed in trilayer graphene.

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Presenters

  • Han Peng

    Department of Physics, University of Oxford

Authors

  • Han Peng

    Department of Physics, University of Oxford

  • Niels Schroeter

    physics, university of oxford, Department of Physics, University of Oxford

  • Jianbo Yin

    Peking University

  • Hailin Peng

    Center for Nanochemistry, College of Chemistry and Molecular Engineering, Peking University, Center for Nanochemistry, Beijing National Laboratory for Molecular Sciences (BNLMS), College of Chemistry and Molecular Engineering, Peking University, Peking University

  • Yulin Chen

    Physics department, University of Oxford, University of Oxford, Oxford Unv., physics, university of oxford, Department of Physics, University of Oxford, Condensed Matter Physics, University of Oxford