Role of random edge-disorder on the transport properties of ultra-thin zig-zag graphene nanoribbons

We report on an introductory study used to gauge the significance of random weakedge disorder on the coherent transport properties of ultra-thin zig-zag nanoribbons (ZGNRs) beyond the simple (i.e., first nearest-neighbour) tight-binding approximation. Such extensions include up to third nearest-neighbour hopping in an extended tight-binding model, as well as a mean-field Hubbard-U . The effect of the random weak-edge disorder causes charge-carrier localization that reduces the conductance about the Fermi energy in all of the systems studied. In the non-interacting systems, the extended tight-binding model is found to be more robust against disorder due to the increased kinetic degrees of freedom. Localization effects from the random weak-edge disorder are found to compete with the mean-field Hubbard-U resulting in spin-dependent conductance properties.