Transport analysis of graphene-based devices with width discontinuities

We have developed a code for the simulation of graphene-based devices consisting of cascaded armchair sections with width discontinuities, in the presence of a generic potential landscape. This is based on a scattering-matrix approach and on the solution of the Dirac equation in the reciprocal space. The presence of width discontinuities requires a particular treatment of the continuity equation for the wave function on the two inequivalent sublattices. Validation has been performed via a comparison with the results of a tight-binding calculation, for a sample with a size small enough to be amenable to this latter approach. Our method can be applied to graphene devices with a size up to a few microns, which is computationally prohibitive for tight-binding techniques.