Volume 54, Number 2, April 2001
|Page(s)||241 - 247|
|Section||Condensed matter: electronic structure, electrical, magnetic, and optical properties|
|Published online||01 December 2003|
Orbital and spin Kondo effects in a double quantum dot
Materials Physics Laboratory,
Helsinki University of Technology - Helsinki, Finland
2 Institut für Theoretische Festkörperphysik, Universität Karlsruhe 76128 Karlsruhe, Germany
3 Forschungszentrum Karlsruhe, Institut für Nanotechnologie 76021 Karlsruhe, Germany
Accepted: 2 February 2001
Motivated by recent experiments, in which the Kondo effect has been observed for the first time in a double quantum dot structure, we study electron transport through a system consisting of two ultrasmall, capacitively coupled dots with large level spacing and charging energy. Due to strong interdot Coulomb correlations, the Kondo effect has two possible sources, the spin and orbital degeneracies, and it is maximized when both occur simultaneously. The large number of tunable parameters allows a range of manipulations of the Kondo physics —in particular, the Kondo effect in each dot is sensitive to changes in the state of the other dot. For a thorough account of the system dynamics, the linear and non-linear conductance is calculated in perturbative and non-perturbative approaches. In addition, the temperature dependence of the resonant peak heights is evaluated in the framework of a renormalization group analysis.
PACS: 73.23.Hk – Coulomb blockade; single-electron tunnelling / 72.15.Qm – Scattering mechanisms and Kondo effect
© EDP Sciences, 2001
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