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Evolution of charge modulation in twisted bilayer graphene near the magic angle

ORAL

Abstract

Twisting and stacking two layers of graphene with a twist-angle near "magic angle" flattens the energy band and significantly slows down the movement of charge carriers. The resulting strong electron-electron interactions favors the emergence of novel correlated phases, including a charge ordered stripe phase[1]. Using STM on magic-angle twisted bilayer graphene with a gate tunable doping dependence, we study the evolution of the band structure with doping and its effect on the charge ordered state. When the flat band is empty or full it produces a pronounced STS spectroscopy peak which corresponds to a peak in the density of states. Bringing the Fermi level within the flat band we observe a correlation induced pseuodogap at the Fermi energy accompanied by a spatial variation of the charge distribution that breaks the C3 symmetry. We will report on the evolution of the charge ordered phase with temperature, magnetic field and on its relation to the pseudogap.

[1] Y. Jiang, X. Lai, K. Watanabe, T. Taniguchi, K. Haule, J. Mao, E.Y. Andrei, Charge order and broken rotational symmetry in magic-angle twisted bilayer graphene, Nature, 573 (2019) 91-95.

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Presenters

  • Xinyuan Lai

    Rutgers University, New Brunswick, Department of Physics and Astronomy, Rutgers University, 136 Frelinghuysen Road, Piscataway, NJ 08855 USA, Rutgers Univeristy

Authors

  • Xinyuan Lai

    Rutgers University, New Brunswick, Department of Physics and Astronomy, Rutgers University, 136 Frelinghuysen Road, Piscataway, NJ 08855 USA, Rutgers Univeristy

  • Nikhil Tilak

    Rutgers University, New Brunswick, Department of Physics and Astronomy, Rutgers University, 136 Frelinghuysen Road, Piscataway, NJ 08855 USA

  • Yuhang Jiang

    University of Chinese Academy of Sciences, Department of Physics and Astronomy, University of Chinese Academy of Sciences, CM5J+7X, Huaibeizhen, Huairou, Beijing, China

  • Jinhai Mao

    University of Chinese Academy of Sciences, Department of Physics and Astronomy, University of Chinese Academy of Sciences, CM5J+7X, Huaibeizhen, Huairou, Beijing, China

  • Mingyu Xu

    Iowa State University, Ames Laboratory and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA, Ames Laboratory, Iowa State University, Dept. of Physics and Astronomy, Ames, Ames Laboratory, Iowa State University

  • Raquel de Almeida Ribeiro

    Iowa State University, Ames Laboratory and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA

  • Paul C Canfield

    Iowa State University, Ames Laboratory and Iowa State University, Ames Lab, Ames Laboratory and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA, Ames laboratory, Ames, IA, Ames Laboratory, Iowa State University, Department of Physics & Astronomy, Iowa State University/Ames Laboratory, Department of Physics and Astronomy, Iowa State University/Ames Laboratory, Iowa State University and Ames Laboratory, Iowa State University, Ames Laboratory, Department of Physics and Astronomy, Iowa State University, Division of Materials Sciences & Engineering, Ames Lab and Iowa State University, Department of Physics and Astronomy, Ames Laboratory/Iowa State Univeristy, Iowa State University/Ames Laboratory

  • Eva Andrei

    Rutgers University, New Brunswick, Department of Physics and Astronomy, Rutgers University, 136 Frelinghuysen Road, Piscataway, NJ 08855 USA, Rutgers Univeristy, Department of physics and Astronomy, Rutgers University