SU(4) versus SU(2) Kondo effect in double quantum dot

TL;DR

This paper investigates the transition between SU(4) and SU(2) Kondo effects in a double quantum dot system, analyzing how electron exchange influences the Kondo temperature and how these effects can be experimentally distinguished.

Contribution

It provides a detailed analysis of the transition between SU(4) and SU(2) Kondo effects in double quantum dots, including the dependence on Zeeman field and exchange interactions.

Findings

Kondo temperature slightly drops in the intermediate regime.

Two types of Kondo effects can be distinguished by Zeeman field sensitivity.

Dependence of Kondo temperature on magnetic field and exchange strength analyzed.

Abstract

We consider the spin and orbital Kondo effect in a parallel arrangement of two strongly electrostatically coupled quantum dots. Increasing the exchange of electrons between the dots through the attached leads induces the transition between the SU(4) spin- and orbital Kondo effect and SU(2) spin Kondo effect. Being the same for the SU(4) and SU(2) symmetry points, the Kondo temperature drops slightly in the intermediate regime. Experimentally, two kinds of Kondo effects can be discriminated by the sensitivity to the suppression of the spin Kondo effect by Zeeman field. The dependence of Kondo temperature on Zeeman field and the strength of electronic exchange mediated by the leads is analyzed in detail.