  We present numerical studies of conduction in graphene nanoribbons with
reconstructed edges based on the standard tight-binding model of the graphene
and the extended Huckel model of the reconstructed defects. We performed atomic
geometry relaxation of individual defects using density functional theory and
then explicitly calculated the tight-binding parameters used to model electron
transport in graphene with reconstructed edges. The calculated conductances
reveal strong backscattering and electron-hole asymmetry depending on the edge
and defect type. This is related to an additional defect-induced band whose
wave function is poorly matched to the propagating states of the pristine
ribbon. We find a transport gap to open near the Dirac point and to scale
inversely with the ribbon width, similarly to what has been observed in
experiments. We predict the largest transport gap to occur for armchair edges
with Stone-Wales defects, while heptagon and pentagon defects cause about equal
backscattering for electrons and holes, respectively. Choosing the heptagon
defect as an example, we show that although electron interactions in the
Hartree approximation cause accumulation of charge carriers on the defects,
surprisingly, their effect on transport is to reduce carrier backscattering by
the defects and thus to enhance the conductance.
