The influence of Coulomb correlations on nonequilibrium quantum transport in quadruple quantum-dot structure

TL;DR

This paper investigates how Coulomb correlations affect quantum transport in a quadruple quantum-dot system under bias, revealing negative differential conductance caused by Fano resonances and discussing methods to enhance this effect.

Contribution

It introduces a combined nonequilibrium Green's functions and equation-of-motion approach to analyze Coulomb effects in QQD transport, highlighting the role of anisotropic kinetics and Fano resonances.

Findings

Coulomb correlations induce negative differential conductance in QQD.

Anisotropy in kinetic processes influences transport behavior.

Strategies to enhance peak-to-valley ratio are discussed.

Abstract

The description of quantum transport in a quadruple quantum-dot structure (QQD) is proposed taking into account the Coulomb correlations and nonzero bias voltages. To achieve this goal the combination of nonequilibrium Green's functions and equation-of-motion technique is used. It is shown that the anisotropy of kinetic processes in the QQD leads to negative differential conductance (NDC). The reason of the effect is an interplay of the Fano resonances which are induced by the interdot Coulomb correlations. Different ways to increase the peak-to-valley ratio related to the observed NDC are discussed.