Electronic Transport of Graphene Nanoribbons: Effect of Edges and Geometry

We discuss the low-energy electronic states and transport properties of graphene nanoribbons. In zigzag nanoribbons with long-ranged impurities, a single perfectly conducting channel emerges associated with such a chiral mode due to edge states, i.e. the absence of the localization. In armchair nanoribbons, the single-channel transport subjected to long-ranged impurities is nearly perfectly conducting, where the backward scattering matrix elements in the lowest order vanish as a manifestation of internal phase structures of the wavefunction. Our numerical simulations reveal the unusual electronic transport properties of graphene nanoribbons as quantum wires.