Charge transfer statistics of a molecular quantum dot with strong electron-phonon interaction

TL;DR

This paper develops a theoretical framework to analyze the full counting statistics of electron transport in a molecular quantum dot with strong electron-phonon interactions, capturing key features of the strong coupling regime.

Contribution

The authors introduce a diagrammatic scheme based on the Lang-Firsov transformation to exactly incorporate electron-phonon interactions in the FCS of a quantum dot.

Findings

Formalism accurately describes strong coupling transport properties

Comparison with Monte Carlo data validates the approach

Captures essential features of nonequilibrium charge transfer

Abstract

We analyze the nonequilibrium transport properties of a quantum dot with a harmonic degree of freedom (Holstein phonon) coupled to metallic leads, and derive its full counting statistics (FCS). Using the Lang-Firsov (polaron) transformation, we construct a diagrammatic scheme to calculate the cumulant generating function. The electron-phonon interaction is taken into account exactly, and the employed approximation represents a summation of a diagram subset with respect to the tunneling amplitude. By comparison to Monte Carlo data the formalism is shown to capture the basic properties of the strong coupling regime.