Mobility gaps in disordered graphene-based materials: an ab initio-based tight-binding approach to mesoscopic transport

As is common knowledge, armchair graphene nanoribbons (aGNRs) share many electronic features with carbon nanotubes (CNTs). Nevertheless, crucial differences emerge when disorder comes into play. It is thus instructive, both from a theoretical and a technological perspective, to analyze the impact of possible types of disorder on the transport properties of these graphene-based materials. Here we report such a comparative study between CNTs and GNRs, which points out the similarities and differences emerging as a consequence of doping by substitutional boron and nitrogen impurities. The role of edge defects (absent in CNTs) is also contrasted with chemical doping disorder. All disorder models have been derived from accurate ab initio calculations of the electronic structures. [GRAPHICS] Conductance as a function of the energy for the (left) single boron dopant, (center) nitrogen dopant, (left) edge defect case, for a 35-aGNR (left and right) and for a (10,10) CNT (center). Red dashed curves: Results for the fully ab initio Hamiltonian. Black solid lines: Results for the tight-binding Hamiltonian with the tuned parametrization (see text). (C) 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim