Electron transport in nanotube-molecular-wire hybrids - art. no. 045416

We study contact effects on electron transport across a molecular wire sand wiched between two semiinfinite (cal bon) nanotube leads as a model for nan oelectrodes. Employing the Landauer scattering matrix approach, we find tha t the conductance is very sensitive to parameters such as the coupling stre ngth and geometry of the contact. The conductance exhibits markedly differe nt behavior in the two limiting scenarios of single contact and multiple co ntacts between the molecular. wire and the nanotube interfacial atoms. In c ontrast to a single contact, the multiple-contact configuration acts as a f ilter selecting single transport channels. It exhibits a scaling law for th e conductance as a function of coupling strength and tube diameter. We also observe an unusual narrow-to-broad-to-narrow behavior of conductance reson ances upon decreasing the coupling..