Phonon-assisted current noise in molecular junctions

TL;DR

This paper analyzes how phonon scattering influences electronic current noise in molecular junctions, deriving an analytic expression and predicting significant inelastic noise contributions in specific molecular setups.

Contribution

It introduces an extended non-equilibrium Green's functions approach to analytically describe phonon-assisted current noise in molecular junctions with weak electron-phonon coupling.

Findings

Derived an analytic expression for current noise at arbitrary temperature.

Identified distinct voltage-dependent contributions to noise.

Predicted significant inelastic noise effects in deuterium molecular junctions.

Abstract

We investigate the effects of phonon scattering on the electronic current noise through nanojunctions using the non-equilibrium Green's functions formalism extended to include the counting field. In the case of weak electron-phonon coupling and a single broad electronic level we derive an analytic expression for the current noise at arbitrary temperature and identify physically distinct contributions based on their voltage dependence. We apply our theory to the experimentally relevant case of a deuterium molecule placed in a break-junction and predict a significant inelastic contribution to the current noise.