Effective contact model for transport through weakly-doped graphene

Recent investigations address transport through ballistic charge-neutral graphene strips coupled to doped graphitic leads. This paper shows that identical transport properties arise when the leads are replaced by quantum wires. This duality between graphitic and metallic leads originates in the selection of modes with transverse momentum close to the K points, and can be extended to a wide class of contact models. Among this class we identify a simple, effective contact model, which provides an efficient tool to study the transport through extended weakly-doped graphitic systems.