Coulomb blockade effects in driven electron transport

TL;DR

This study numerically investigates how strong Coulomb repulsion affects electron transport in driven molecular wires, revealing that Coulomb blockade sharpens resonance peaks but minimally impacts electron pumping and current suppression.

Contribution

It introduces a Floquet-based numerical approach to analyze Coulomb effects in driven molecular wires, highlighting their influence on resonance and transport phenomena.

Findings

Coulomb repulsion sharpens resonance peaks in current.

Temperature broadens the resonance peaks.

Coulomb blockade minimally affects electron pumping and current suppression.

Abstract

We study numerically the influence of strong Coulomb repulsion on the current through molecular wires that are driven by external electromagnetic fields. The molecule is described by a tight-binding model whose first and last site is coupled to a respective lead. The leads are eliminated within a perturbation theory yielding a master equation for the wire. The decomposition into a Floquet basis enables an efficient treatment of the driving field. For the electronic excitations in bridged molecular wires, we find that strong Coulomb repulsion significantly sharpens resonance peaks which broaden again with increasing temperature. By contrast, Coulomb blockade has only a small influence on effects like non-adiabatic electron pumping and coherent current suppression.