Repository logo
 

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

Accepted version
Peer-reviewed

Change log

Authors

Abstract

jats:titleAbstract</jats:title>jats:pGraphene on hexagonal boron nitride (hBN) can exhibit a topological phase via mutual crystallographic alignment. Recent measurements of nonlocal resistance (jats:italicR</jats:italic>jats:subnl</jats:sub>) 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 jats:italicR</jats:italic>jats:subnl</jats:sub> at SDP is negligible, but below 60 K approaches the value of jats:italich</jats:italic>/2jats:italice</jats:italic>jats:sup2</jats:sup> 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.</jats:p>

Description

Keywords

51 Physical Sciences, 5104 Condensed Matter Physics

Journal Title

Communications Physics

Conference Name

Journal ISSN

2399-3650
2399-3650

Volume Title

3

Publisher

Springer Science and Business Media LLC

Rights

All rights reserved
Sponsorship
EPSRC (1578382)
European Commission (656485)
Engineering and Physical Sciences Research Council (EP/P026311/1)
The research was funded by the Royal Society and the EPSRC through an EPSRC-JSPS International Network Grant (EP/P026311/1). Y.L. was supported through China Scholarship Council (CSC) Cambridge International Scholarship and Cambridge Trust. M.A. was supported from the MSCA-IFEF-ST Marie Curie (Grant 656485-Spin3), the Agencia Estatal de Investigación of Spain (Grant MAT2016-75955), and the Junta de Castilla y León (Grant SA256P18). T.H. and G.P.M were supported by the Foundation for Polish Science through the IRA Programme co-financed by EU within SG OP. G.P.M. was supported by the National Science Center (Poland) through ETIUDA fellowship (Grant No. UMO-2017/24/T/ST3/00501).