Interlayer electron-hole friction in tunable twisted bilayer graphene semimetal

ORAL

Abstract

Charge-neutral conducting systems represent a class of materials with unusual properties governed by electron-hole (e-h) interactions. Depending on the quasiparticles' statistics, band structure, and device geometry these semimetallic phases of matter can feature unconventional responses to external fields that often defy simple interpretations in terms of single-particle physics. In this talk, we will show that small-angle twisted bilayer graphene (SA-TBG) offers a highly-tunable system in which to explore interactions-limited electron conduction. We will see that by employing a dual-gated device architecture one can tune SA-TBG devices from a non-degenerate charge-neutral Dirac fluid to a compensated two-component e-h Fermi liquid where spatially separated electrons and holes experience strong mutual friction [1]. This friction is revealed through the T2 resistivity that accurately follows the e-h drag theory we developed. Our results provide a textbook illustration of a smooth transition between different interaction-limited transport regimes and clarify the conduction mechanisms in charge-neutral SA-TBG.

[1] D.A. Bandurin, et al., arXiv:2208.05659 (2022).

*This work was supported by AFOSR grant FA9550-21-1-0319 and the Gordon and Betty Moore Foundation’s EPiQS Initiative through Grant GBMF9463 to P.J.-H. K.W. and T.T. acknowledge support from JSPS KAKENHI (Grant Numbers 19H05790, 20H00354, and 21H05233). A.P. acknowledges support from the European Commission under the EU Horizon 2020 MSCA-RISE-2019 program (project 873028 HYDROTRONICS) and from the Leverhulme Trust under the grant RPG-2019-363.

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Publication: [1] D.A. Bandurin, et al., arXiv:2208.05659 (2022).

Presenters

  • Denis A Bandurin

    • National University of Singapore
    • Massachusetts Institute of Technology

Authors

  • Denis A Bandurin

    • National University of Singapore
    • Massachusetts Institute of Technology

  • Alessandro Principi

    • Univ of Manchester

  • Isabelle Y Phinney

    • Harvard University

  • Takashi Taniguchi

    • National Institute for Materials Science
    • Kyoto Univ
    • International Center for Materials Nanoarchitectonics, National Institute of Materials Science
    • Kyoto University
    • International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-044, Japan
    • International Center for Materials Nanoarchitectonics, National Institute for Materials Science
    • National Institute for Materials Science, Japan
    • National Institute For Materials Science
    • NIMS
    • National Institute for Material Science
    • International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Japan
    • NIMS Japan

  • Kenji Watanabe

    • National Institute for Materials Science
    • Research Center for Functional Materials, National Institute of Materials Science
    • Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-044, Japan
    • NIMS
    • Research Center for Functional Materials, National Institute for Materials Science
    • National Institute for Materials Science, Japan
    • Research Center for Functional Materials, National Institute for Materials Science, Tsukuba, Japan
    • NIMS Japan

  • Pablo Jarillo-Herrero

    • Massachusetts Institute of Technology MIT