Quantum Hall Effect in Hydrogenated Graphene

Abstract

The quantum Hall effect is observed in a two-dimensional electron gas formed in millimeter-scale hydrogenated graphene, with a mobility less than $10\text{ }\text{ }{\mathrm{cm}}^{2}/\mathrm{V}\ifmmode\cdot\else\textperiodcentered\fi{}\mathrm{s}$ and corresponding Ioffe-Regel disorder parameter $({k}_{F}\ensuremath{\lambda}{)}^{\ensuremath{-}1}\ensuremath{\gg}1$. In a zero magnetic field and low temperatures, the hydrogenated graphene is insulating with a two-point resistance of the order of $250h/{e}^{2}$. The application of a strong magnetic field generates a negative colossal magnetoresistance, with the two-point resistance saturating within 0.5% of $h/2{e}^{2}$ at 45 T. 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.