Transport in undoped graphene is related to percolating current patterns in the networks of $n$- and $p$-type regions reflecting the strong bipolar charge density fluctuations. Finite transparency of the $p\mathrm{\text{−}}n$ junctions is vital in establishing the macroscopic conductivity. We propose a random resistor network model to analyze scaling dependencies of the conductance on the doping and disorder, the quantum magnetoresistance and the corresponding dephasing rate.

• Received 20 June 2007

DOI:https://doi.org/10.1103/PhysRevLett.99.176801