First-principles calculation on the conductance of ruthenium-quasi cumulene-ruthenium molecular junctions

Abstract

The conductance of a family of ruthenium-quasi cumulene-ruthenium molecular junctions including different numbers of carbon atoms, both in even numbers and odd numbers, are investigated using a fully self-consistent ab initio approach which combines the non-equilibrium Green’s function formalism with density functional theory. Our calculations demonstrate that although the overall transport properties of the Ru-quasi cumulene-Ru junctions with an even number of carbon atoms are different from those of the junctions with an odd number of carbon atoms, the difference between the corresponding currentvoltage (I-V) characteristics of these molecular junctions declines to lesser than 16% when the voltage goes up. In each group, the molecular junctions give a large transmission around the Fermi level since the Ru-C πbonds can extend the π conjugation of the carbon chains into the Ru electrodes, and their I-Vcharacteristics are almost linear and independent of the chain length, illustrating potential applications as conducting molecular wires in future molecular electronic devices and circuits.

Keywords

molecular electronic devices / density functional theory / non-equilibrium Green’s function / carbon monatomic chains

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