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arXiv · 0904.0948

Gap opening in the zeroth Landau level of graphene

A. J. M. Giesbers·L. A. Ponomarenko·K. S. Novoselov·A. K. Geim·M. I. Katsnelson·J. C. Maan·U. Zeitler
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Abstract

We have measured a strong increase of the low-temperature resistivity $\rho_{xx}$ and a zero-value plateau in the Hall conductivity $\sigma_{xy}$ at the charge neutrality point in graphene subjected to high magnetic fields up to 30 T. We explain our results by a simple model involving a field dependent splitting of the lowest Landau level of the order of a few Kelvin, as extracted from activated transport measurements. The model reproduces both the increase in $\rho_{xx}$ and the anomalous $\nu=0$ plateau in $\sigma_{xy}$ in terms of coexisting electrons and holes in the same spin-split zero-energy Landau level.

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A. J. M. Giesbers, L. A. Ponomarenko, K. S. Novoselov, A. K. Geim, M. I. Katsnelson, J. C. Maan, U. Zeitler. 2009-04-06. Gap opening in the zeroth Landau level of graphene. https://doi.org/10.1103/physrevb.80.201403

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