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HAIT Journal of Science and Engineering A Volume 5, Issues 1-2, pp. 93-111 © 2008 Holon Institute of Technology | |||
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From spin and orbital SU(4) to spin SU(2) Kondo effect in double quantum dot
Alexander Chudnovskiy1, Frank Hellmuth1,
and Victor Kagalovsky2,*
1Institut für Theoretische Physik, Universität Hamburg, | Jungiusstr. 9, 20355 Hamburg, Germany 2Sami Shamoon College of Engineering, Beer-Sheva 84100, Israel *Corresponding author: victork@sce.ac.il Received 21 September 2007
| We consider 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 smooth crossover between 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 effect can be discriminated by the sensitivity to the suppression of the spin Kondo effect by Zeeman field. The dependence of the Kondo temperature and of the differential conductance on the strength of electronic exchange through the leads and Zeeman field is analyzed in detail. PACS: 73.23.-b, 73.63.Kv, 72.15.Qm |