Dresden 2006 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 9: Poster I
HL 9.104: Poster
Montag, 27. März 2006, 15:15–17:45, P3
Magnetization of a tunneling coupled double-layer electronsystem and double-layer quantum dots — •O. Rösler1, J. Topp1, D. Reuter2, A.D. Wieck2, and D. Grundler1 — 1Institut für Angewandte Physik und Zentrum für Mikrostrukturforschung, Universität Hamburg, Jungiusstraße 11, D-20355 Hamburg — 2Ruhr-Universität Bochum, Lehrstuhl für Angewandte Festkörperphysik, Universitätsstraße 150, D-44780 Bochum
We have experimentally investigated the magnetization of a double-layered two dimensional electron system and of double-layered quantum dots. The heterostructure was grown by molecular-beam epitaxy. It consisted of two 15 nm wide GaAs quantum wells. These were separated by a narrow tunneling barrier consisting of Al0.33Ga0.66As with a thickness of 1 nm. Delta-doping layers on both sides of the double-quantum well was integrated to provide electrons. The doping layers were optimized to get an approximately symmetric conduction band profile i.e., a balanced electron system. The magnetization shows sawtooth like quantum oscillations at even and odd total filling factors in magnetic fields B up to 33 T. With increasing angle between double-layer normal and B specific filling factors appear and disappear. This unexpected behaviour will be studied in further detail in a mixing chamber cryostat providing a temperature down to 10 mK. Here, we will also investigate quantum dots prepared from the same wafer. We report on our last results.
The authors thank D. Heitmann for continuous support and the Deutsche Forschungsgemeinschaft for financial support via SFB 508.