2024-03-28T12:02:51Zhttp://digital.csic.es/dspace-oai/requestoai:digital.csic.es:10261/1268032016-02-18T03:32:51Zcom_10261_10252com_10261_3col_10261_10253
Lafont, F.
Ribeiro, Rebeca
Cresti, A.
Cummings, Aron W.
Roche, Stephan
2015-12-14T11:42:24Z
2015-12-14T11:42:24Z
2014
Physical Review B 90(11): 115422 (2014)
http://hdl.handle.net/10261/126803
10.1103/PhysRevB.90.115422
http://dx.doi.org/10.13039/501100000780
http://dx.doi.org/10.13039/501100001665
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.
eng
http://creativecommons.org/licenses/by/3.0/
openAccess
Anomalous dissipation mechanism and Hall quantization limit in polycrystalline graphene grown by chemical vapor deposition
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