Capacitively coupled double quantum dot system in the Kondo regime

TL;DR

This paper investigates how capacitive coupling influences the low-temperature Kondo physics in a double quantum dot system, revealing that inter-dot Coulomb repulsion significantly enhances the second-stage Kondo temperature.

Contribution

It provides a detailed numerical analysis of the impact of inter-dot Coulomb interaction on the two-stage Kondo effect in a double quantum dot system using a multi-impurity Anderson model.

Findings

Inter-dot Coulomb repulsion drastically affects the two-stage Kondo effect.

The second-stage Kondo temperature increases exponentially with inter-dot Coulomb repulsion.

The study offers insights for experimental observation of the two-stage Kondo effect.

Abstract

A detailed study of the low-temperature physics of an interacting double quantum dot system in a T-shape configuration is presented. Each quantum dot is modeled by a single Anderson impurity and we include an inter-dot electron-electron interaction to account for capacitive coupling that may arise due to the proximity of the quantum dots. By employing a numerical renormalization group approach to a multi-impurity Anderson model, we study the thermodynamical and transport properties of the system in and out of the Kondo regime. We find that the two-stage-Kondo effect reported in previous works is drastically affected by the inter-dot Coulomb repulsion. In particular, we find that the Kondo temperature for the second stage of the two-stage-Kondo effect increases exponentially with the inter-dot Coulomb repulsion, providing a possible path for its experimental observation.