Conductance Through a Redox System in the Coulomb Blockade Regime: Many-Particle Effects and Influence of Electronic Correlations

TL;DR

This paper studies electron transport in a redox system within the Coulomb blockade regime, revealing many-particle effects and how electronic correlations influence current-voltage behavior, including phenomena like negative differential resistance.

Contribution

It introduces a detailed Hubbard model with Coulomb interactions and bosonic coupling to analyze complex transport phenomena in redox systems.

Findings

Transport shows deviations from single-electron models at high voltages.

Negative differential resistance observed under certain Coulomb interaction conditions.

Current enhancement occurs depending on Coulomb and reorganization energies.

Abstract

We investigate the transport characteristics of a redox system weakly coupled to leads in the Coulomb blockade regime. The redox system comprises a donor and acceptor separated by an insulating bridge in a solution. It is modeled by a two-site extended Hubbard model which includes on-site and inter-site Coulomb interactions and the coupling to a bosonic bath. The current voltage characteristics is calculated at high temperatures using a rate equation approach. For high voltages exceeding the Coulomb repulsion at the donor site the calculated transport characteristics exhibit pronounced deviations from the behavior expected from single-electron transport. Depending on the relative sizes of the effective on-site and inter-site Coulomb interactions on one side and the reorganization energy on the other side we find negative differential resistance or current enhancement.