Tuning Coulomb interactions in moiré graphene with planar scanning probes

ORAL

Abstract

Moiré van der Waals heterostructure devices have demonstrated a wide array of emergent quantum electronic phases, including unconventional superconductivity and correlated insulators in magic angle twisted bilayer graphene and related graphitic systems. Coulomb interactions have been shown to play a role in the formation or suppression of these states. However, previous experiments exploring Coulomb screening by measuring devices with different gate dielectric thicknesses have been limited by the inherent variability between devices of the twist angle and other disorder sources. Dynamic control of the Coulomb interaction strength in a local device region, where the twist angle remains relatively constant, has yet to be demonstrated. Using a scanning probe terminated by a few-micron diameter metallic plane parallel to a moiré heterostructure, we can determine the twist angle in a local region, then increase the screening of Coulomb interactions in that region by lowering the probe toward the device. We report on the operation of this novel experimental system and preliminary results on how emergent electronic states in 2D heterostructures are affected by changes in electron-electron interactions.

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Presenters

  • Laurel E Anderson

    • University of Washington
    • Harvard University

Authors

  • Laurel E Anderson

    • University of Washington
    • Harvard University

  • Chadwick Evans

    • University of Washington

  • Arnab Manna

    • University of Washington

  • Salima N Mayanja

    • University of Washington

  • José Mendoza

    • University of Washington

  • Jordan M Fonseca

    • University of Washington

  • Jiaqi Cai

    • University of Washington

  • Andrew M Vincent

    • Augusta University

  • Takashi Taniguchi

    • Kyoto Univ
    • National Institute for Materials Science
    • Research Center for Materials Nanoarchitectonics
    • Research Center for Materials Nanoarchitectonics, National Institute for Materials Science
    • National Institute for Materials Sciences
    • NIMS
    • International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
    • National Institute for Material Science
    • International Center for Materials Nanoarchitectonics, NIMS, Japan
    • International Center for Materials Nanoarchitectonics, Tsukuba
    • National Institue for Materials Science
    • Kyoto University
    • National Institute of Materials Science
    • International Center for Materials Nanoarchitectonics and National Institute for Materials Science

  • Kenji Watanabe

    • National Institute for Materials Science
    • NIMS
    • Research Center for Electronic and Optical Materials, National Institute for Materials Science
    • Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
    • National Institute for Material Science

  • Xiaodong Xu

    • University of Washington

  • Arthur W Barnard

    • University of Washington