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

Published version
Peer-reviewed

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Authors

Amado, Mario 
Mazur, Grzegorz. P. 
Robinson, Jason W. A.  ORCID logo  https://orcid.org/0000-0002-4723-722X

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.

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

Keywords

Article, /639/766/1130/2798, /639/301/357/918/1052, article

Journal Title

Communications Physics

Conference Name

Journal ISSN

2399-3650

Volume Title

3

Publisher

Nature Publishing Group UK
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)