Effects due to backscattering and pseudogap features in graphene nanoribbons with single vacancies

We present a systematic study of electron backscattering phenomena during conduction for graphene nanoribbons with single-vacancy scatterers and dimensions within the capabilities of modern lithographic techniques. Our analysis builds upon an ab initio parameterized semiempirical model that breaks electron-hole symmetry and nonequilibrium Green's-function methods for the calculation of the conductance distribution g. The underlying mechanism is based on wave-function localizations and perturbations that in the case of the first pi-pi* plateau can give rise to impuritylike pseudogaps with both donor and acceptor characteristics. Confinement and geometry are crucial for the manifestation of such effects. Self-consistent quantum transport calculations characterize vacancies as local charging centers that can induce electrostatic inhomogeneities on the ribbon topology.