J. Wilhelm, M. Walz, F. Evers

Phys. Rev. B 89, 195406 (2014)

We calculate the local current density in pristine armchair graphene nanoribbons (AGNRs) with varying width, NC, employing a density-functional-theory-based ab initio transport formalism. We observe very pronounced current patterns (“streamlines”) with threefold periodicity in NC. They arise as a consequence of quantum confinement in the transverse flow direction. Neighboring streamlines are separated by stripes of almost vanishing flow. As a consequence, the response of the current to functionalizing adsorbates is very sensitive to their placement: adsorbates located within the current filaments lead to strong backscattering, while adsorbates placed in other regions have almost no impact at all.