Hyperbolic enhancement of photocurrent patterns in minimally twisted bilayer graphene

ORAL

Abstract

Quasi-periodic moiré patterns and their effect on electronic properties of twisted bilayer graphene (TBG) have been intensely studied. At small twist angles θ, due to atomic reconstruction, the moiré superlattice morphs into a network of narrow domain walls separating micron-scale AB and BA stacking regions. We use scanning probe photocurrent imaging to resolve nanoscale variations of the Seebeck coefficient occurring at these domain walls. The observed features become enhanced in a range of mid-infrared frequencies where the hexagonal boron nitride (hBN), which we use as a TBG substrate, is optically hyperbolic. Our results illustrate new capabilities of nano-photocurrent technique for probing nanoscale electronic inhomogeneities in two-dimensional materials.

–

Presenters

  • Sai Sunku

    • Columbia University
    • Columbia Univ
    • Physics, Columbia University

Authors

  • Sai Sunku

    • Columbia University
    • Columbia Univ
    • Physics, Columbia University

  • Dorri Halbertal

    • Columbia University
    • Columbia Univ
    • Physics, Columbia University

  • Tobias Stauber

    • Instituto de Ciencia de Materiales de Madrid (CSIC), Madrid
    • ICMM, CSIC, Madrid
    • Instituto de Ciencias de Materiales de Madrid
    • Consejo Superior de Investigaciones Cientificas (CSIC)

  • Shaowen Chen

    • Columbia Univ
    • Physics, Columbia University

  • Alexander S McLeod

    • Columbia University
    • Department of Physics, Columbia University
    • Columbia Univ

  • Andrey Rikhter

    • UC San Diego
    • University of California, San Diego

  • Michael Berkowitz

    • Columbia University
    • Columbia Univ

  • Chiu Fan Bowen Lo

    • Columbia Univ
    • Columbia University

  • Derick Gonzalez-Acevedo

    • Columbia Univ
    • Physics, Columbia University

  • James Hone

    • Columbia Univ
    • Columbia University
    • Department of Mechanical Engineering, Columbia University
    • Mechanical Engineering, Columbia University

  • Cory Dean

    • Columbia University
    • Department of Physics, Columbia University
    • Physics, Columbia University
    • Columbia Univ

  • Michael Fogler

    • University of California, San Diego
    • Department of Physics, University of California San Diego
    • UC San Diego
    • Department of Physics, University of California, San Diego
    • UCSD
    • University of California San Diego

  • Dmitri Basov

    • Columbia University
    • Department of Physics, Columbia University
    • Physics, Columbia University
    • Columbia Univ