Vibrationally dependent electron-electron interactions in resonant electron transport through single-molecule junctions

TL;DR

This paper explores how vibrationally dependent electron-electron interactions influence electron transport in single-molecule junctions, revealing effects on cooling, heating, negative differential resistance, and conductance asymmetries.

Contribution

It introduces a model extension that incorporates vibrationally dependent electron-electron interactions into electron transport analysis.

Findings

Vibrationally dependent interactions significantly affect local cooling and heating.

The interactions can induce negative differential resistance.

Pronounced asymmetries appear in conductance maps due to these interactions.

Abstract

We investigate the role of electronic-vibrational coupling in resonant electron transport through single-molecule junctions, taking into account that the corresponding coupling strengths may depend on the charge and excitation state of the molecular bridge. In the presence of multiple electronic states, this requires to extend the commonly used model and include vibrationally dependent electron-electron interaction. We use Born-Markov master equation methods and consider selected models to exemplify the effect of the additional interaction on the transport characteristics of a single-molecule junction. In particular, we show that it has a significant influence on local cooling and heating mechanisms, may result in negative differential resistance, and cause pronounced asymmetries in the conductance map of a single-molecule junction.