Abstract
By applying the nonequilibrium Green function method, we have theoretically investigated the quantum transport properties of armchair and zigzag graphene nanoribbons (GNRs), with defects (vacancies) appearing at the edges or in the inner part. Effects of the defects on the electronic conductance and local density of states are comprehensively studied. It is found that both edge and inner defects reduce the electronic conductance in general, while in detail they have different effects on the transport properties for different combinations of defect location and GNR edge type. Under the same theoretical framework, we have also studied the effects of dephasing scattering processes in the GNRs, employing two specific choices of self-energy that provide momentum-conserving or momentum-relaxing dephasing processes. The momentum-relaxing dephasing processes not only relax momentum but also add an additional resistance to the channel, while the momentum- conserving dephasing processes only break the phase and have much less effect on the resistance. It is found that the transport properties of metallic zigzag GNRs are much more strongly modified by the dephasing scattering processes than are those of semiconducting armchair GNRs.
Published Version
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