Department of Physics, McGill University, Montréal, Quebec, H3A 2T8, Canada.
Phys Rev Lett. 2013 Apr 26;110(17):176801. doi: 10.1103/PhysRevLett.110.176801. Epub 2013 Apr 22.
The quantum Hall effect is observed in a two-dimensional electron gas formed in millimeter-scale hydrogenated graphene, with a mobility less than 10 cm2/V·s and corresponding Ioffe-Regel disorder parameter (k(F)λ)(-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/e2. The application of a strong magnetic field generates a negative colossal magnetoresistance, with the two-point resistance saturating within 0.5% of h/2e2 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.
量子霍尔效应在毫米级氢化石墨烯中形成的二维电子气中被观测到，迁移率小于 10 cm2/V·s，相应的 Ioffe-Regel 无序参数 (k(F)λ)(-1) ≫ 1。在零磁场和低温下，氢化石墨烯是绝缘的，两点电阻约为 250h/e2。强磁场的应用产生了负的庞磁电阻，在 45 T 时两点电阻在 h/2e2 的 0.5%以内饱和。我们的观察结果与在石墨烯的态密度中打开杂质诱导的能隙一致。讨论了二维原子晶体中由缺陷散射引起的电子局域化和磁场限制之间的相互作用。
