J. Guillemette, S. S. Sabri, B. Wu, K. Bennaceur, P. E. Gaskell, M. Savard, P. L. Lévesque, F. Mahvash, A. Guermoune, M. Siaj, R. Martel, T. Szkopek, G. Gervais
The quantum Hall effect is observed in a two-dimensional electron gas formed in millimeter-scale hydrogenated graphene, with a mobility less than 10 $\mathrm{cm^{2}/V\cdot s}$ and corresponding Ioffe-Regel disorder parameter $(k_{F}\lambda)^{-1}\gg1$. In zero magnetic field and low temperatures, the hydrogenated graphene is insulating with a two-point resistance of order of $250 h/e^2$. Application of a strong magnetic field generates a negative colossal magnetoresistance, with the two-point resistance saturating within 0.5% of $h/2e^{2}$ at 45T. Our observations are consistent with the opening of an impurity-induced gap in the density of states of graphene. The interplay between electron localization by defect scattering and magnetic confinement in two-dimensional atomic crystals is discussed.
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http://arxiv.org/abs/1301.1257
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