Quantum Hall Effect in Hydrogenated Graphene

TL;DR

This study demonstrates the quantum Hall effect in hydrogenated graphene with low mobility, showing a magnetic-field-induced transition from insulating to quantum Hall states, highlighting impurity effects and electron localization.

Contribution

First observation of quantum Hall effect in hydrogenated graphene with high disorder, revealing impurity-induced gap formation and magnetoresistance behavior.

Findings

Quantum Hall effect observed at high magnetic fields in hydrogenated graphene.

Strong negative magnetoresistance saturates near $h/2e^2$ at 45T.

Hydrogenated graphene exhibits impurity-induced gap and localization effects.

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 $\mathrm{cm^{2}/V\cdot s}$ 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.