Kondo Effect in Multiple-Dot Systems

TL;DR

This paper analytically investigates the Kondo effect in multiple-dot systems, revealing how inter-dot interactions influence conductance, with exact solutions applied to double and triple-dot configurations.

Contribution

It introduces an analytical approach using the Bethe-ansatz solution for multi-dot systems, extending understanding of Kondo physics beyond single-dot models.

Findings

Inter-dot Kondo effect can both enhance and suppress conductance.

Gate voltage and magnetic field control the Kondo-induced conductance.

Characteristic transport properties are identified in triple-dot systems.

Abstract

We study the Kondo effect in multiple-dot systems for which the inter- as well as intra-dot Coulomb repulsions are strong, and the inter-dot tunneling is small. The application of the Ward-Takahashi identity to the inter-dot dynamical susceptibility enables us to analytically calculate the conductance for a double-dot system by using the Bethe-ansatz exact solution of the SU(4) impurity Anderson model. It is clarified how the inter-dot Kondo effect enhances or suppresses the conductance under the control of the gate voltage and the magnetic field. We then extend our analysis to multiple-dot systems including more than two dots, and discuss their characteristic transport properties by taking a triple-dot system as an example.