Anomalous dissipation mechanism and Hall quantization limit in polycrystalline graphene grown by chemical vapor deposition
Lafont, F. (Laboratoire National de Métrologie et d'Essais)
Ribeiro-Palau, Rebeca (Laboratoire National de Métrologie et d'Essais)
Han, Z. (Institut polytechnique de Grenoble. Institut Néel)
Cresti, Alessandro (Institut polytechnique de Grenoble. Institute of Microelectronics, Electromagnetism and Photonics)
Delvallée, Alexandra (Laboratoire National de Métrologie et d'Essais)
Cummings, Aron (Institut Català de Nanociència i Nanotecnologia)
Roche, Stephan (Institut Català de Nanociència i Nanotecnologia)
Bouchiat, Vincent (Institut polytechnique de Grenoble. Institut Néel)
Ducourtieux, Sebastien (Laboratoire National de Métrologie et d'Essais)
Schopfer, F. (Laboratoire National de Métrologie et d'Essais)
Poirier, W. (Laboratoire National de Métrologie et d'Essais)

Date:	2014
Abstract:	We report on the observation of strong backscattering of charge carriers in the quantum Hall regime of polycrystalline graphene, grown by chemical vapor deposition, which alters the accuracy of the Hall resistance quantization. The temperature and magnetic field dependence of the longitudinal conductance exhibits unexpectedly smooth power-law behaviors, which are incompatible with a description in terms of variable range hopping or thermal activation but rather suggest the existence of extended or poorly localized states at energies between Landau levels. Such states could be caused by the high density of line defects (grain boundaries and wrinkles) that cross the Hall bars, as revealed by structural characterizations. Numerical calculations confirm that quasi-one-dimensional extended nonchiral states can form along such line defects and short circuit the Hall bar chiral edge states.
Note:	Ajuts: it has been performed within the EMRP (European Metrology Research Program), project SIB51, Graphohm. The EMRP is jointly funded by the EMRP participating countries within EURAMET (European association of national metrology institutes) and the European Union.
Rights:	Tots els drets reservats.
Language:	Anglès
Document:	Article ; recerca ; Versió acceptada per publicar
Published in:	Physical review B : Condensed matter and materials physics, Vol. 90, issue 11 (Sep. 2014) , art. 115422, ISSN 1550-235X

DOI: 10.1103/PhysRevB.90.115422

Postprint 6 p, 979.5 KB

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Research literature > UAB research groups literature > Research Centres and Groups (research output) > Experimental sciences > Catalan Institute of Nanoscience and Nanotechnology (ICN2)
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