Measurement of topological Berry phase in highly disordered graphene

Abstract

We have observed the quantum Hall effect (QHE) and Shubnikov--de Haas (SdH) oscillations in highly disordered graphene at magnetic fields up to 65 T. Disorder was introduced by hydrogenation of graphene up to a ratio H/C $\ensuremath{\approx}0.1%$. The analysis of SdH oscillations and QHE indicates that the topological part of the Berry phase, proportional to the pseudospin winding number, is robust against introduction of disorder by hydrogenation in large-scale graphene.