Detecting topological currents in graphene superlattices
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Levitov_Detecting.pdf
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1.19 MB
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Author(s)
Gorbachev, R. V.
Yu, G. L.
Kretinin, A. V.
Withers, F.
Cao, Y.
Mishchenko, A.
Grigorieva, I. V.
Novoselov, Kostya S.
Geim, A. K.
Song, Justin Chien Wen
Date Issued
September 2014
Journal
Science
Publisher
American Association for the Advancement of Science (AAAS)
Citation
Gorbachev, R. V., J. C. W. Song, G. L. Yu, A. V. Kretinin, F. Withers, Y. Cao, A. Mishchenko, et al. “Detecting Topological Currents in Graphene Superlattices.” Science (September 11, 2014).
Version
Author's final manuscript
Abstract
Topological materials may exhibit Hall-like currents flowing transversely to the applied electric field even in the absence of a magnetic field. In graphene superlattices, which have broken inversion symmetry, topological currents originating from graphene's two valleys are predicted to flow in opposite directions and combine to produce long-range charge neutral flow. We observe this effect as a nonlocal voltage at zero magnetic field in a narrow energy range near Dirac points at distances as large as several microns away from the nominal current path. Locally, topological currents are comparable in strength to the applied current, indicating large valley-Hall angles. The long-range character of topological currents and their transistor-like control by gate voltage can be exploited for information processing based on the valley degrees of freedom.
MIT Department
Massachusetts Institute of Technology. Department of Physics
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Creative Commons Attribution-Noncommercial-Share Alike
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DOI of Published Version
https://doi.org/10.1126/science.1254966
