Using a generalized Landauer approach we study the nonlinear transport in mesoscopic graphene with zigzag and armchair edges. We find that for clean systems, the low-bias low-temperature conductance, $G$, of an armchair edge system is quantized as $G∕\tilde{t}=4n{e}^2∕h$, whereas for a zigzag edge the quantization changes to $G∕\tilde{t}=4(n+1∕2)e^2∕h$, where $\tilde{t}$ is the transmission probability and $n$ is an integer. We also study the effects of a nonzero bias, temperature, and magnetic field on the conductance. The magnetic field dependence of the quantization plateaus in these systems is somewhat different from the one found in the two-dimensional electron gas due to a different Landau level quantization.

• Received 21 December 2005

DOI:https://doi.org/10.1103/PhysRevB.73.195411