Valley Hall effect and nonlocal resistance in locally gapped graphene

Thomas Aktor, Jose H. Garcia, Stephan Roche, Antti-Pekka Jauho, and Stephen R. Power
Phys. Rev. B 103, 115406 – Published 4 March 2021
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Abstract

We report on the emergence of bulk, valley-polarized currents in graphene-based devices, driven by spatially varying regions of broken sublattice symmetry, and revealed by nonlocal resistance (RNL) fingerprints. By using a combination of quantum transport formalisms, giving access to bulk properties as well as multiterminal device responses, the presence of a nonuniform local band gap is shown to give rise to valley-dependent scattering and a finite Fermi-surface contribution to the valley Hall conductivity, related to characteristics of RNL. These features are robust against disorder and provide a plausible interpretation of controversial experiments in graphene/hexagonal boron nitride superlattices. Our findings suggest both an alternative mechanism for the generation of valley Hall effect in graphene and a route towards valley-dependent electron optics, by materials and device engineering.

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  • Received 18 September 2019
  • Accepted 18 February 2021

DOI:https://doi.org/10.1103/PhysRevB.103.115406

©2021 American Physical Society

Physics Subject Headings (PhySH)

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

Thomas Aktor1, Jose H. Garcia2, Stephan Roche2,3, Antti-Pekka Jauho1, and Stephen R. Power4,*

  • 1Center for Nanostructured Graphene, DTU Physics, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark
  • 2Catalan Institute of Nanoscience and Nanotechnology, CSIC and The Barcelona Institute of Science and Technology, Campus UAB, Bellaterra, 08193 Barcelona (Cerdanyola del Vallès), Spain
  • 3Institució Catalana de Recerca i Estudis Avançats, 08070 Barcelona, Spain
  • 4School of Physics, Trinity College Dublin, Dublin 2, Ireland

  • *stephen.power@tcd.ie

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Issue

Vol. 103, Iss. 11 — 15 March 2021

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