Vibration-induced inelastic effects in the electron transport through multisite molecular bridges

TL;DR

This paper introduces a semi-phenomenological model based on Buttiker's dephasing approach to analyze inelastic electron transport effects caused by vibrational phonons in molecular junctions, validated against Green's function calculations.

Contribution

A new analytical approach using Buttiker's dephasing model for studying inelastic effects in multilevel molecular electron transport.

Findings

The model accurately reproduces results from Green's function calculations for single-level systems.

It provides a simplified analytical framework for multilevel molecular junctions.

The approach elucidates the role of vibrational phonons in inelastic tunneling spectra.

Abstract

We theoretically analyzed inelastic effects in the electron transport through molecular junctions originating from electron-vibron interactions. The molecular bridge was simulated by a periodic chain of identical interacting hydrogen-like atoms providing a set of energy states for the electron tunneling. To avoid difficulties inevitably arising when advanced computational techniques are employed to study inelastic electron transport through multilevel bridges, we propose and develop a semiphenomenological approach. The latter is based on the Buttiker's dephasing model within the scattering matrix formalism. The advantage of the proposed approach is that it allows to analytically study various inelastic effects on the conduction through molecular junctions including multilevel bridges. Here, we apply this approach to describe features associated with electron energy transfer to vibrational phonons which appear in the inelastic tunneling spectra of electrons. In the particular case of a single level bridge our results agree with those obtained by self-consitent calculations carried out within the nonequilibrium Green's functions method validating the usefulness of the suggested approach.