Molecular transport junctions: Current from electronic excitations in the leads

TL;DR

This paper demonstrates that electron-hole excitations in the leads can significantly influence current in molecular junctions, sometimes surpassing elastic tunneling contributions, especially in molecules with strong charge transfer transitions.

Contribution

It introduces a model showing how coupling to electron-hole excitations can dominate molecular junction conduction, highlighting a new mechanism affecting current flow.

Findings

Electron-hole excitations can significantly affect molecular junction current.

In some cases, electron-hole contributions exceed elastic tunneling.

Charge transfer transitions amplify the effect of electron-hole excitations.

Abstract

Using a model comprising a 2-level bridge connecting free electron reservoirs we show that coupling of a molecular bridge to electron-hole excitations in the leads can markedly effect the source-drain current through a molecular junction.In some cases, e.g. molecules that exhibit strong charge transfer transitions, the contribution from electron-hole excitations can exceed the Landauer elastic current and dominate the observed conduction.