Edge modes and non-local conductance in graphene superlattices

Rory Brown, Niels Walet, Francisco Guinea

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    Abstract

    We study the existence of edge modes in gapped Moiré superlattices of graphene monolayer ribbons on a hexagonal boron nitride substrate. We find that the superlattice bands acquire finite Chern numbers, which lead to a Valley Hall Effect. The presence of dispersive edge modes is confirmed by calculations of the band structure of realistic nanoribbons using tight binding methods. These edge states are only weakly sensitive to disorder, as short-range scattering processes lead to mean free paths of the order of microns. The results explain the existence of edge currents when the chemical potential lies within the bulk superlattice gap, and offer an explanation for existing non-
    local resistivity measurements in graphene ribbons on boron nitride.
    Original languageEnglish
    Article number026802
    JournalPhysical Review Letters
    Volume120
    Issue number2
    DOIs
    Publication statusPublished - 12 Jan 2018

    Keywords

    • edge modes
    • graphene
    • conductance

    Research Beacons, Institutes and Platforms

    • Advanced materials

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