Lack of universal conductance features in disordered graphene nanoribbons

Abstract

Recent experimental characterisation of graphene flakes has demonstrated the existence of local structural alterations of the ideal honeycomb lattice whose influence on the conductance mechanism of this material has not yet been fully evaluated. In this study a numerical statistical analysis of the conductance distribution function in disordered graphene nanoribbons is presented. Calculations are performed in statistically equivalent replica large systems within the Non Equilibrium Green's Function formalism. Different kinds of local scattering centers have been considered. A characteristic general behavior of the conductance variance in these quasi one‐dimensional systems is the linear scaling with the average of logarithm of the conductance, in the localization regime. However, in a broad class of realization of the local disorder, the slope is not a constant as the disorder degree varies in any region of the energy spectrum, i.e. the single parameters scaling hypothesis is not verified (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Conductance distribution in doped and defected graphene nanoribbons

“…9 However, these findings have to be confirmed in more realistic descriptions of graphene-based conductors, since the Anderson model is a rather idealized realization of the real disorder ͑or the real chemical modification͒ that could be approximately valid in the case of a huge density of local scattering centers. 10 In this work, we have extensively investigated, by means of ab initio calibrated models and nonequilibrium Green's function ͑NEFG͒ techniques, the effects of the inclusion of controlled densities of local scattering centers, i.e., vacancies ͑V's͒ and N impurities, in the conductance distribution function of large ͑up to ϳ1 m͒ Armchair GNRs ͑AGNRs͒. Simulations have been performed for large replicas of equivalent systems and results represent statistical averages over conductance-related properties.…”