Regensburg 2013 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 91: Poster Session: Quantum dots and wires: preparation & characterization & optical properties & transport properties
HL 91.28: Poster
Donnerstag, 14. März 2013, 16:00–20:00, Poster A
Magnetic field modulation of RKKY interaction between quantum dots — •Alexander W. Heine1, Katharina Janzen2, Brendan Coughlan2, Daniel Tutuc1, Gertrud Zwicknagl2, and Rolf J. Haug1 — 1Institut für Festkörperphysik, Leibniz Universität Hannover, 30167 Hannover, Germany — 2Institut für Mathematische Physik, Technische Universität Braunschweig, 38106 Braunschweig, Germany
The spin of a quantum dot is proposed as a possible realization of a qubit in quantum information processes. One possible mechanism to control the spin of a quantum dot beyond the nearest neighbour approach is the Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction, an indirect exchange between magnetic moments. To probe the RKKY interaction between two quantum dots, we use the Kondo effect as spectroscopic tool. At low temperatures between 25 mK and 900 mK and high magnetic field of 5 T we measure the differentieal conductance of the quantum dots. In the presence of RKKY interaction we observe a qualitative change of the temperature dependence with variation of the magnetic field.
Modelling our system and calculating the interaction strength by evaluating the Lindhard function yields the variation with magnetic field of the indirect exchange. We theoretically analyze the magnetic-field tuning of the Kondo singlet formation in a double-dot system.