Cryogenic near-field imaging of twist angle disorder in twisted bilayer graphene

ORAL

Abstract

Twisted bilayer graphene has emerged as a versatile platform to study strongly correlated phenomena and superconductivity. These properties only occur near the magic angle of 1.1 degree, and allow for little twist angle inhomogeneity. Recent works have shown the widespread twist angle disorder and strain in such samples, which are found to be a limiting factor for the existence of strongly correlated states. Yet, these works required the use of highly specialized experimental setups. Here we report on cryogenic (10 K) near-field photovoltage measurements, in which the photoresponse turns out to be a sensitive probe to map the twist angle within our device. Strengthened by nanoscale absorption measurements, we interpret our observations using the photothermoelectric effect, in which the resistive states at the full-filling carrier density act as sensitive probes of small twist angle variations. Our work demonstrates that cryogenic near-field photovoltage mapping is a powerful and accessible technique for studying the optical and optoelectronic properties of twisted bilayer graphene on the nanoscale.

–

Publication: In preparation: Probing twist angle variations in twisted bilayer graphene with photovoltage nanoscopy

Presenters

  • Niels Hesp

    • ICFO - The Institute of Photonic Sciences
    • ICFO-The Institute of Photonic Sciences

Authors

  • Niels Hesp

    • ICFO - The Institute of Photonic Sciences
    • ICFO-The Institute of Photonic Sciences

  • Petr Stepanov

    • ICFO
    • ICFO-The Institute of Photonic Sciences

  • Sergi Batlle

    • ICFO - The Institute of Photonic Sciences
    • ICFO-The Institute of Photonic Sciences

  • Daniel Rodan-Legrain

    • Massachusetts Institute of Technology MI

  • Iacopo Torre

    • ICFO - The Institute of Photonic Sciences
    • ICFO—Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Castelldefels (Barcelona), Spain

  • Hitesh Agarwal

    • Institute of Photonic Sciences, Mediterranean Technology Park
    • ICFO - The Institute of Photonic Sciences
    • ICFO-The Institute of Photonic Sciences

  • Roshan Krishna Kumar

    • Lancaster Univ
    • Institute of Photonic Sciences, Mediterranean Technology Park
    • ICFO - The Institute of Photonic Sciences

  • Kenji Watanabe

    • NIMS
    • Research Center for Functional Materials, National Institute for Materials Science
    • National Institute of Materials Science
    • National Institue for Materials Science
    • National Institute for Materials Science, Japan
    • National Institute for Materials Science (NIMS)
    • National Institute of Materials Science, Tsukuba, Japan
    • National Institute for Materials Science
    • NIMS, Japan

  • Takashi Taniguchi

    • National Institute for Materials Science, Tsukuba, Japan
    • National Institute for Materials Science
    • NIMS
    • Kyoto Univ
    • International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Ibaraki 305-0044, Japan.
    • 3 National Institute for Materials Science, Tsukuba, Japan
    • National Institute for Materials Science; 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
    • National Institute of Materials Science, Tsukuba, Japan
    • National Institute of Materials Science
    • Advanced Materials Laboratory, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan
    • National Institute for Materials Science (Japan)
    • International Center for Materials Nanoarchitectonics, National Institute for Materials Science
    • International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
    • Kyoto University
    • International Center for Materials Nanoarchitectonics
    • International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Japan
    • International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Japan
    • International Center for Materials Nanoarchitectonics, National Institute for MaterialsScience, 1-1 Namiki, Tsukuba 305-0044, Japan
    • National Institute for Material Science, Japan
    • National Institute for Material Science
    • National Institute of Material Sciences, Japan
    • NIMS, Tsukuba
    • 2National Institute for Materials Science, Namiki 1-1, Ibaraki 305-0044, Japan.
    • National Institute of Materials Science, Tsukuba, Ibaraki 305-0044, Japan
    • National Institute for Materials Science, Japan
    • International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science, 1-1 Namiki Tsukuba, Ibaraki 305-0044, Japan.
    • NIMS, Japan
    • National Institute for Materials Science (NIMS)
    • NIMS. Japan
    • International Center for Material Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Japan
    • International Center for Material Nanoarchitectonics, National Institute for Materials Science
    • National Institute for Materials Science Tsukuba
    • National Institute for Materials Science, 1-1 Namiki
    • National Institute for Materials Science of Japan
    • National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
    • NIMS - National Institute for Material Science, Japan
    • International Center for Materials Nanoarchitectonics, National Institute for Material Science, Tsukuba, Ibaraki 305-0044, Japan.
    • National Institute for Material Science, Tsukuba
    • National Institute for Materials Science, International Center for Materials Nanoarchitectonics
    • International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
    • National Institute of Material Science
    • National Institute for Materials Science,1-1 Namiki, Tsukuba, 305-0044, Japan

  • Pablo Jarillo-Herrero

    • Massachusetts Institute of Technology MI
    • Massachusetts Institute of Technology

  • Frank Koppens

    • ICFO-The Institute of Photonic Sciences
    • ICFO-The Institute of Photonic Sciences; ICREA-Institució Catalana de Recerca i Estudis Avançats, Barcelona, Spain