Many Body Effects on the Transport Properties of Single-Molecule Devices

TL;DR

This paper investigates how many-body interactions, including electron-electron and electron-phonon effects, influence the conductance of single-molecule devices, revealing regimes akin to the Kondo effect and charge polarization phenomena.

Contribution

It applies the Numerical Renormalization Group method to analyze conductance in molecular devices, uncovering new regimes of behavior related to strong electron-phonon coupling and charge polarization.

Findings

Low-temperature conductance aligns with the standard Kondo model.

Strong electron-phonon coupling induces a charge Kondo effect.

Gate voltage causes significant polarization and rectification effects.

Abstract

The conductance through a molecular device including electron-electron and electron-phonon interactions is calculated using the Numerical Renormalization Group method. At low temperatures and weak electron-phonon coupling the properties of the conductance can be explained in terms of the standard Kondo model with renormalized parameters. At large electron-phonon coupling a charge analog of the Kondo effect takes place that can be mapped into an anisotropic Kondo model. In this regime the molecule is strongly polarized by a gate voltage which leads to rectification in the current-voltage characteristics of the molecular junction.