Topological valley currents via ballistic edge modes in graphene superlattices near the primary Dirac point

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Authors
  Li, Yang
Amado, Mario
  Hyart, Timo
Mazur, Grzegorz. P.
  Robinson, Jason W. A.
Publication Date
2020-12-04
Journal Title
Communications Physics
Publisher
Nature Publishing Group UK
Volume
3
Issue
1
Language
en
Type
Article
This Version
VoR
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Citation
Li, Y., Amado, M., Hyart, T., Mazur, G. P., & Robinson, J. W. A. (2020). Topological valley currents via ballistic edge modes in graphene superlattices near the primary Dirac point. Communications Physics, 3 (1) https://doi.org/10.1038/s42005-020-00495-y
Description
Funder: China Scholarship Council (CSC); doi: https://doi.org/10.13039/501100004543
Funder: Fundacja na rzecz Nauki Polskiej (Foundation for Polish Science); doi: https://doi.org/10.13039/501100001870
Abstract
Abstract: Graphene on hexagonal boron nitride (hBN) can exhibit a topological phase via mutual crystallographic alignment. Recent measurements of nonlocal resistance (Rnl) near the secondary Dirac point (SDP) in ballistic graphene/hBN superlattices have been interpreted as arising due to the quantum valley Hall state. We report hBN/graphene/hBN superlattices in which Rnl at SDP is negligible, but below 60 K approaches the value of h/2e2 in zero magnetic field at the primary Dirac point with a characteristic decay length of 2 μm. Furthermore, nonlocal transport transmission probabilities based on the Landauer-Büttiker formalism show evidence for spin-degenerate ballistic valley-helical edge modes, which are key for the development of valleytronics.
Keywords
Article, /639/766/1130/2798, /639/301/357/918/1052, article
Sponsorship
Consejería de Educación, Junta de Castilla y León (Consejería de Educación de la Junta de Castilla y León) (SA256P18)
Narodowe Centrum Nauki (National Science Centre) (UMO-2017/24/T/ST3/00501)
Royal Society (EP/P026311/1)
RCUK | Engineering and Physical Sciences Research Council (EPSRC) (EP/P026311/1)
Identifiers
s42005-020-00495-y, 495
External DOI: https://doi.org/10.1038/s42005-020-00495-y
This record's URL: https://www.repository.cam.ac.uk/handle/1810/314762
Rights
Attribution 4.0 International (CC BY 4.0)
Licence URL: https://creativecommons.org/licenses/by/4.0/
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Attribution 4.0 International (CC BY 4.0)
Except where otherwise noted, this item's licence is described as Attribution 4.0 International (CC BY 4.0)