Quantum Hall Effect in Hydrogenated Graphene

The quantum Hall effect is observed in a two-dimensional electron gas formed in millimeter-scale hydrogenated graphene, with a mobility less than 10 cm(2)/V . s and corresponding Ioffe-Regel disorder parameter (k(F)lambda)(-1) >> 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/2e(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. DOI: 10.1103/PhysRevLett.110.176801