Investigating the influence of electrode Miller indices alteration on electronic transport in thiophene-based...

Electrical charge transport through thiophene-dithiol-based molecular wires attached to gold electrodes with three different types of crystallographic orientations (<1,1,1>, <1,1,0 > and <1,0,1 >) was investigated. Electron transport in the systems under consideration was evaluated systematically by analyzing current values, transmission spectrum, projected device density of states and zero bias orbital analysis utilizing density functional theory in conjunction with non-equilibrium Green's function. Investigations proved that tuning of conductance in nano-molecular junctions is possible through different electrode orientations. As the HOMO-LUMO gap in the <1,1,0 > oriented thiophene dithiol junction is drastically less than that of the other configurations under consideration, the <1,1,0 > configuration exhibited superior constructive conductance in comparison to other junction orientations. This provided us with ideas for designing pioneering hetero-cyclic nano-scale electronics devices. Also, <1,1,0 > has been found to show negative differential conductance behavior above +2.6 V and below -2.6 V, and hence has potential applications in oscillating and switching circuits.