Berlin 2005 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 17: Poster Ib
HL 17.32: Poster
Freitag, 4. März 2005, 16:30–19:00, Poster TU F
Classical Analysis of Trajectories in an Open Quantum Dot — •Roland Brunner1, R. Meisels1, F. Kuchar1, M. Elhassan2, J. Bird3, and K. Ishibashi4 — 1Department of Physics, University of Leoben, Austria — 2Department of Electrical Engineering, Arizona State University, USA — 3Department of Electrical Engineering,University at Buffalo The State University of New York — 4Semiconductor Laboratory, RIKEN, Saitama, Japan
Transport in sub-micron semiconductor structures is an important topic of low-dimensional electron physics. Among other possibilities small structures can be realized in the form of electron billiards, e.g. quantum dots, when the electron mean free path is larger than the region to which the electrons are confined. Then and for low currents, the transport can be described classically by the ballistic motion of single electrons. In this work, we address the question of stable trajectories in open quantum dots and their contribution to prominent structure in the low-field magnetoresistance. We present a classical model which allows to vary the confinement potential, deviations from circular symmetry, the entrance angle of the electrons (focussing), and the number of dots in series. We show in which regions of entrance angles backscattering peaks in the low-field magnetoresistance occur. We find that a smooth (parabolic) confinement potential describes the experimental magnetoresistance traces significantly better than a hard wall potential. For the backscattering regions we calculate the trajectories in a single open quantum dot and observe that all of them are regular and not chaotic.