Modeling Heterogeneous Junction Properties using Metal Electrodes
Abstract
We have studied the effects of the interfacial bond arrangement on the electronic transport features of nano junction. The transport properties of finite, defect-free armchair and zigzag single-walled carbon nanotubes attached to metallic contacts have been calculated by means of the non-equilibrium Green functional formalism with the Tight-Binding and the Extended Hückel Hamiltonians. For different electrodes and changing nanotube interface positions, an overall complex behavior of the transmission spectra due to band mixing and interference has been observed. The comparison of the two models shows that the Tight Binding approach fails to give a satisfactory representation of the transmission function when a more accurate description of the C-C and Cu-C chemical bonds has to be considered. The effect of interface geometry variance on conduction has been examined and found that contact-nanotube distance has a significant impact, while contact-nanotube symmetry has a marginal, yet significant role.