Regensburg 2004 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 44: Poster II
HL 44.32: Poster
Donnerstag, 11. März 2004, 16:30–19:00, Poster A
Classical and quantum-mechanical behavior of the magneto-resistance in open quantum dots — •Roland Brunner1, Ronald Meisels1, Friedemar Kuchar1, Mohamed Elhassan2, Jon Bird2, and Koji Ishibashi3 — 1Department of Physics, University of Leoben, Austria — 2Department of Elecctrical Engineering, ASU, USA — 3Semiconductor Laboratory, Saitama, Riken, Japan
We report on the investigation of ballistic magneto-transport in open AlGaAs/GaAs dots and its response to microwaves in the frequency range around 50 GHz. The results allow to distinguish between backscattering peaks and Shubnikov-de-Haas oscillations in the transition range from classical to quantum-mechanical behaviour. /par A particularly interesting aspect of the physics of quantum dots regards the crossover from the classical to the quantum-mechanical regime in open dots. In this contribution we focus on the behaviour exhibited by open quantum dots in low and medium magnetic fields. Open quantum dots are strongly coupled to the 2DEG reservoirs via short constrictions. /par The experiments were carried out in an array of three dots which were defined by contiguous finger gate structures on top of a two dimensional electron system in AlGaAs/GaAs using electron beam lithography. The connections to neighbouring dots and to the 2DEG reservoirs are made by constrictions (lithographic width 70 nm). The electronic dot diameter was determined to be 185 nm. The experimental results are discussed with respect to quasi-classical and quantum-mechanical calculations. Work supported by FWF, project 15513, Austria.