Effect of dimensionality on the localization behavior in hydrogenated graphene systems

Recently, several experiments have shown that graphene exhibits a metal-to-insulator transition by hydrogenation. Here we theoretically study the transport properties of hydrogenated graphene and graphene nanoribbons (GNRs), focusing on the conductance fluctuation behavior in the localized regime. Using a simple model for the conductance distribution in the quasi-localized regime where the conventional theory fails, we derive the modified single parameter scaling (SPS) relations for quasi-one-dimensional (Q1D) GNRs as well as two-dimensional (2D) graphene. We show that, as the dimensional crossover occurs from 2D to Q1D, the shape of the conductance distribution evolves from a positively skewed distribution to a log-normal distribution. We predict that GNRs with widths much larger than the localization lengths do not behave as a Q1D system. Our results provide fundamental insights into the dimensionality change not only in graphene, but also in general mesoscopic systems in the localized regime.