Vibrationally Mediated Control of Single Electron Transmission in Weakly Coupled Molecule-Metal Junctions

TL;DR

This paper introduces a method to control single-electron transmission in molecular junctions by exploiting vibrational modes, enabling electron flow modulation through vibrational excitation near molecular resonances.

Contribution

It presents a novel mechanism for controlling electron transmission using vibrational excitation, supported by DFT analysis of a benzene-Au junction.

Findings

Vibrational modes can induce single-electron transmission.

Control of electron flow is possible by external vibrational excitation.

The mechanism is effective near molecular resonances.

Abstract

We propose a mechanism which allows one to control the transmission of single electrons through a molecular junction. The principle utilizes the emergence of transmission sidebands when molecular vibrational modes are coupled to the electronic state mediating the transmission. We will show that if a molecule-metal junction is biased just below a molecular resonance one may induce the transmission of a single electron by externally exciting a vibrational mode of the molecule. The analysis is quite general but requires that the molecular orbital does not hybridize strongly with the metallic states. As an example we perform a density functional theory (DFT) analysis of a benzene molecule between two Au(111) contacts and show that exciting a particular vibrational mode can give rise to transmission of a single electron