Web of Science: 7 cites, Scopus: 6 cites, Google Scholar: cites,
Deciphering the origin of nonlocal resistance in multiterminal graphene on hexagonal-boron-nitride with ab initio quantum transport : fermi surface edge currents rather than Fermi sea topological valley currents
Marmolejo Tejada, J.M. (University of Delaware. Department of Physics and Astronomy)
Garcia, José H. (Institut Català de Nanociència i Nanotecnologia)
Petrović, M. D. (University of Delaware. Department of Mathematical Sciences)
Chang, P-H (University of Nebraska Lincoln. Department of Physics and Astronomy)
Sheng, X-L (University of Delaware. Department of Mathematical Sciences)
Cresti, Alessandro (Université Grenoble Alpes)
Plecháč, P. (University of Delaware. Department of Mathematical Sciences)
Roche, Stephan (Institut Català de Nanociència i Nanotecnologia)
Nikolić, B.K. (University of Delaware. Department of Physics and Astronomy)

Data: 2018
Resum: The recent observation (Gorbachev et al 2014 Science 346 448) of nonlocal resistance R NL near the Dirac point (DP) of multiterminal graphene on aligned hexagonal-boron nitride (G/hBN) has been interpreted as the consequence of topological valley Hall currents carried by the Fermi sea states just beneath the bulk gap E g induced by inversion symmetry breaking. However, the corresponding valley Hall conductivity ${ \sigma }_{{xy}}^{v} $, quantized inside E g , is not directly measurable. Conversely, the Landauer-Büttiker formula, as a numerically exact approach to observable nonlocal transport quantities, yields R NL ≡ 0 for the same simplistic Hamiltonian of gapped graphene that generates ${ \sigma }_{{xy}}^{v}\ne 0 $ via the Kubo formula. We combine ab initio with quantum transport calculations to demonstrate that G/hBN wires with zigzag edges host dispersive edge states near the DP that are absent in theories based on the simplistic Hamiltonian. Although such edge states exist also in isolated zigzag graphene wires, aligned hBN is required to modify their energy-momentum dispersion and generate ${ R}_{\mathrm{NL}}\ne 0 $ near the DP. The Fermi surface-determined edge currents carrying the nonlocal signal persist also in the presence of edge disorder and over long distances. Concurrently, they resolve the long-standing puzzle of why the highly insulating state of G/hBN is rarely observed. Thus, we conclude that the observed R NL is unrelated to Fermi sea topological valley currents conjectured for gapped Dirac spectra.
Nota: Número d'acord de subvenció EC/H2020/785219
Nota: Número d'acord de subvenció MINECO/FIS2015-67767-P
Nota: Número d'acord de subvenció MINECO/SEV-2013-0295
Drets: Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan es reconegui l'autoria de l'obra original. Creative Commons
Llengua: Anglès
Document: article ; recerca ; publishedVersion
Matèria: Graphene ; Van der Waals heterostructures ; Valley Hall effect ; Berry curvature ; Edge states
Publicat a: Journal of physics: Materials, Vol. 1, Núm. 1 (September 2018) , art. 015006, ISSN 2515-7639

DOI: 10.1088/2515-7639/aad585


15 p, 1.7 MB

El registre apareix a les col·leccions:
Documents de recerca > Documents dels grups de recerca de la UAB > Centres i grups de recerca (producció científica) > Ciències > Institut Català de Nanociència i Nanotecnologia (ICN2)
Articles > Articles de recerca
Articles > Articles publicats

 Registre creat el 2020-06-18, darrera modificació el 2020-08-30



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