Regensburg 2010 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 46: Quantum Dots and Wires: Transport
HL 46.2: Talk
Wednesday, March 24, 2010, 14:15–14:30, H17
Interaction-induced spin selection in quantum dots — •Maximilian C. Rogge1, Esa Räsänen2, and Rolf J. Haug1 — 1Institut für Festkörperphysik, Leibniz Universität Hannover, Appelstrasse 2, 30167 Hannover, Germany — 2Nanoscience Center, Department of Physics,University of Jyväskylä, FI-40014 Jyväskylä, Finland
We present a combined work of theory and experiment concerning the spectrum of electronic states of a many-electron lateral quantum dot in high magnetic fields. We performed magnetotransport measurements on a quantum dot made with local anodic oxidation and electron beam lithography. Several Coulomb blockade peaks are analyzed in terms of the energetic properties of the involved states. In the 4>ν>2 regime with two Landau levels (LL), with ν being the filling factor of the dot, a pronounced zig-zag pattern is found. This can roughly be understood with the constant interaction model, that uses the single electron excitation spectrum (Fock-Darwin) plus a constant Coulomb repulsion energy. However, detailed analysis reveals, that this model can only be applied to the data from the zeroth LL with a spin-dependent bimodal structure. Data from the first LL show different behavior without bimodality. To understand this phenomenon, many-electron calculations within spin-density-functional theory were performed. As a result, interaction-induced spin polarization is found in the first LL.