Inelastic effects in molecular junctions in the Coulomb and Kondo regimes: Nonequilibrium equation-of-motion approach

TL;DR

This paper develops a self-consistent nonequilibrium equation-of-motion approach to study inelastic effects in electron transport through molecular junctions, capturing vibrational features in Coulomb blockade and Kondo regimes.

Contribution

It introduces a novel self-consistent nonequilibrium EOM scheme that qualitatively reproduces experimental vibrational features in molecular junctions, extending previous equilibrium methods.

Findings

Qualitative agreement with experimental vibrational features

Reproduction of equilibrium EOM results in the appropriate limit

Effective modeling of inelastic effects in Coulomb and Kondo regimes

Abstract

Inelastic effects in the Coulomb blockade and Kondo regimes of electron transport through molecular junctions are considered within a simple nonequilibrium equation-of-motion (EOM) approach. The scheme is self-consistent, and can qualitatively reproduce the main experimental observations of vibrational features in Coulomb blockade [H.Park et al., Nature 407, 57 (2000)] and Kondo [L.H.Yu et al., Phys. Rev. Lett. 93, 266802 (2004)] regimes. Considerations similar to the equilibrium EOM approach by Meir et al. [Phys. Rev. Lett. 66, 3048 (1991); ibid. 70, 2601 (1993)] are used on the Keldysh contour to account for the nonequilibrium nature of the junction, and dressing by appropriate Franck-Condon (FC) factors is used to account for vibrational features. Results of the equilibrium EOM scheme by Meir et al. are reproduced in the appropriate limit.