Europhys. Lett.
Volume 71, Number 4, August 2005
Page(s) 672 - 678
Section Condensed matter: electronic structure, electrical, magnetic, and optical properties
Published online 20 July 2005
Europhys. Lett., 71 (4), pp. 672-678 (2005)
DOI: 10.1209/epl/i2005-10126-y

$\mth{SU(4)}$ vs. $\mth{SU(2)}$ Kondo effect in double quantum dot

A. L. Chudnovskiy

1. Institut für Theoretische Physik, Universität Hamburg Jungiusstr. 9, 20355 Hamburg, Germany

received 2 May 2005; accepted in final form 22 June 2005
published online 20 July 2005

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 a 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 the Kondo temperature on Zeeman field and the strength of electronic exchange mediated by the leads is analyzed in detail.

73.23.-b - Electronic transport in mesoscopic systems.
73.63.Kv - Quantum dots.
72.15.Qm - Scattering mechanisms and Kondo effect.

© EDP Sciences 2005