Interference Blockade in the Conductance of Organic Molecules

TL;DR

This study investigates how molecular orientation and isomer type affect the electrical conductance of stilbene molecules connected to carbon nanotubes, revealing interference effects that enable conductance control.

Contribution

It introduces a simple interference rule explaining conductance variations in molecular junctions, enabling straightforward control mechanisms.

Findings

Significant conductance differences between cis/trans isomers.

Conductance varies by orders of magnitude with molecular orientation.

Interference effects explain conductance modulation.

Abstract

The conductance of {\em cis/trans} isomers of stilbene molecules connected to armchair single wall carbon nanotubes is studied in the Landauer formalism combined with a density-functional based approach. For a given arrangement of the electrodes, dramatic differences in the transmission between both isomers are found. For a given isomer, the conductance can be varied by orders of magnitude by changing the molecule-electrode relative orientation. Both effects can be explained by a simple, physically transparent interference rule, which suggests a straightforward conductance control in such molecular systems by different switching mechanisms.