Flat band carrier confinement in magic angle twisted bilayer Graphene

ORAL

Abstract

Magic angle twisted bilayer graphene has emerged as a powerful platform for studying strongly correlated electron physics, owing to its almost dispersionless low-energy, flat, bands and the ability to tune the band filling by electrostatic gating. Techniques to control the twist angle between graphene layers have led to rapid experimental progress but improving sample quality is essential for separating the delicate correlation physics from disorder effects. However, owing to the 2D nature of the system and the relatively low carrier density, the samples are highly susceptible to doping inhomogeneity which can drastically modify the local potential landscape. This potential disorder is distinct from the twist-angle variation which has been studied elsewhere. Using low temperature scanning tunneling spectroscopy we demonstrated that the flat bands in magic angle twisted bilayer graphene can substantially amplify even negligibly small doping inhomogeneity. As a result the charge carriers become confined, obscuring the correlation effects associated with the intrinsic physics of magic-angle twisted bilayer graphene

*Work supported by DOE-FG02-99ER45742; Gordon and Betty Moore Foundation EPIQS GBMF9453; DOE DE-AC02-07CH11358; Gordon and Betty Moore Foundation EPIQS GBMF4411

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Presenters

  • Nikhil Tilak

    • Rutgers University, New Brunswick

Authors

  • Nikhil Tilak

    • Rutgers University, New Brunswick

  • Xinyuan Lai

    • Rutgers University, New Brunswick

  • Shuang Wu

    • Rutgers University, New Brunswick
    • Department of Physics and Astronomy, Rutgers University

  • zhenyuan zhang

    • Rutgers University, New Brunswick

  • Mingyu Xu

    • Ames Laboratory, Iowa State University, Dept. of Physics and Astronomy, Ames
    • Iowa State University/AmesLab
    • Iowa State University

  • RAQUEL DE ALMEIDA RIBEIRO

    • Ames Laboratory, U.S. Department of Energy, and Department of Physics and Astronomy, Iowa State University
    • Ames Lab

  • Paul C Canfield

    • Iowa State University/ Ames Laboratory
    • Ames Laboratory
    • Ames Laboratory, Iowa State University
    • Iowa State University
    • Ames Lab/Iowa State
    • Ames Laboratory, Ames, IA
    • Iowa State University/AmesLab
    • Department of Physics and Astronomy, Iowa State University/Ames Laboratory
    • Department of Physics & Astronomy, Iowa State University/Ames Laboratory
    • Ames Laboratory, U.S. Department of Energy, and Department of Physics and Astronomy, Iowa State University
    • Ames Laboratory/Iowa State University

  • Eva Andrei

    • Rutgers University, New Brunswick
    • Department of Physics and Astronomy, Rutgers University, Piscataway, NJ