Destructive quantum interference in transport through molecules with electron-electron and electron-vibration interactions

TL;DR

This paper investigates how quantum interference effects in molecular junctions persist despite vibrations and Coulomb interactions, enabling large conductance changes useful for molecular quantum transistors.

Contribution

It demonstrates that quantum interference effects remain observable in molecular junctions with electron-electron and vibrational interactions, especially in the Kondo regime, and shows their robustness for device applications.

Findings

Interference effects persist with vibrations and Coulomb interactions.

Conductance can be tuned over orders of magnitude in the Kondo regime.

Large conductance changes are robust at reasonable temperatures and voltages.

Abstract

We study the transport through a molecular junction exhibiting interference effects. We show that these effects can still be observed in the presence of molecular vibrations if Coulomb repulsion is taken into account. In the Kondo regime, the conductance of the junction can be changed by several orders of magnitude by tuning the levels of the molecule, or displacing a contact between two atoms, from nearly perfect destructive interference to values of the order of 2e 2 /h expected in Kondo systems. We also show that this large conductance change is robust for reasonable temperatures and voltages for symmetric and asymmetric tunnel couplings between the source-drain electrodes and the molecular orbitals. This is relevant for the development of quantum interference effect transistors based on molecular junctions.