Upstream modes and antidots poison graphene quantum Hall effect

Moreau, Nicolas;Brun-Barrière, Boris;Somanchi, S.;Watanabe, K.;Hackens, Benoît;et.al.
(2021) Nature Communications — Vol. 12, n° 1, p. 1-7 (2021)

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Authors
  • Moreau, NicolasUCLouvain
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  • Brun-Barrière, Borisorcid-logoUCLouvain
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  • Somanchi, S.JARA-FIT and 2nd Institute of Physics—RWTH Aachen,Germany
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  • Watanabe, K.orcid-logoResearch Center for Functional Materials, National Institute for Materials Science, Tsukuba, Japan.
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Abstract
The quantum Hall effect is the seminal example of topological protection, as charge carriers are transmitted through one-dimensional edge channels where backscattering is prohibited. Graphene has made its marks as an exceptional platform to reveal new facets of this remarkable property. However, in conventional Hall bar geometries, topological protection of graphene edge channels is found regrettably less robust than in high mobility semiconductors. Here, we explore graphene quantum Hall regime at the local scale, using a scanning gate microscope. We reveal the detrimental influence of antidots along the graphene edges, mediating backscattering towards upstream edge channels, hence triggering topological breakdown. Combined with simulations, our experimental results provide further insights into graphene quantum Hall channels vulnerability. In turn, this may ease future developments towards precise manipulation of topologically protected edge channels hosted in various types of two-dimensional crystals.
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Citations

Moreau, N., Brun-Barrière, B., Somanchi, S., Watanabe, K., Taniguchi, T., Stampfer, C., & Hackens, B. (2021). Upstream modes and antidots poison graphene quantum Hall effect. Nature Communications, 12(1), 1-7. https://doi.org/10.1038/s41467-021-24481-2 (Original work published 2021)