Dresden 2011 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 85: Poster Session II
HL 85.103: Poster
Donnerstag, 17. März 2011, 18:00–21:00, P4
Kondo effect in double quantum dots with magnetic field-tuned coupling — Daniel Tutuc1,3, Rolf Haug1,3, •Brendan Coughlan2,3, Lars Musiol2,3, Sabine Tornow2,3, and Gertrud Zwicknagl2,3 — 1Institut für Festkörperphysik, Leibniz Universität Hannover, D-30167 Hannover — 2Institut für Mathematische Physik, Technische Universität Braunschweig, D-38106 Braunschweig — 3NTH School for Contacts in Nano Systems, Braunschweig-Clausthal-Hannover
We study the variation with magnetic field of the Kondo effect in a double quantum dot system coupled via an open conducting region. The transport measurements [1] indicate a competiton between Kondo singlet formation and magnetic alignment via the Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction which has been in the focus of interest in heavy electron systems during the past year. Tuning the coupling by a magnetic field provides insight into the relative importance of the different interactions (excluded volume, RKKY, etc) between Kondo impurities. Novel features originate from the chirality of the coupling in finite magnetic fields. Theoretically we model the double quantum dot system by two Anderson impurities which are both coupled to individual fermionic baths representing the leads as well as to a central fermionic reservoir representing the common source. We calculate equilibrium and transport properties of this model using a variational ansatz for the ground state and discuss the validity of simplified effective coupling models.
[1] Daniel Tutuc et al., arXiv:1010.5692