Kondo temperature and screening extension in a double dot system

TL;DR

This paper investigates the Kondo effect and spin correlations in a double quantum dot system using Slave Boson Mean Field Approximation, analyzing conductance, density of states, and Kondo cloud extension to understand the system's quantum regimes and temperature behavior.

Contribution

It introduces a novel calculation of the Kondo cloud extension and temperature in a double dot system using Slave Boson methods, linking spatial correlations to transport properties.

Findings

Kondo cloud extension depends on inter-dot coupling.

Kondo temperature correlates with the critical temperature from slave boson analysis.

Transport properties vary across different quantum regimes.

Abstract

In this work we use the Slave Boson Mean Field Approximation at finite U to study the effects of spin-spin correlations in the transport properties of two quantum dots coupled in series to metallic leads. Different quantum regimes of this system are studied in a wide range of parameter space. The main aspects related to the interplay between the half-filling Kondo effect and the antiferromagnetic correlation between the quantum dots are reviewed. Slave boson results for conductance, local density of states in the quantum dots, and the renormalized energy parameters, are presented. As a different approach to the Kondo physics in a double dot system, the Kondo cloud extension inside the metallic leads is calculated and its dependence with the inter-dot coupling is analyzed. In addition, the cloud extension permits the calculation of the Kondo temperature of the double quantum dot. This result is very similar to the corresponding critical temperature $T_c$, as a function of the parameters of the system, as obtained by using the finite temperature extension of the Slave Boson Mean Field Approximation.