Regensburg 2007 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 13: Poster 1

HL 13.56: Poster

Montag, 26. März 2007, 15:00–17:30, Poster A

SAW-induced current in ratchets on GaAs/AlGaAs heterostructures as function of dimensionality and temperature. — •Marcin Malecha, Jens Ebbecke, and Achim Wixforth — Universität Augsburg, Institut für Physik, Lehrstuhl für Experimentalphysik I, Universitätsstr. 1, D-86159 Augsburg

Ratchets are basically non-symmetrical systems. In quantum regime, the most important feature of a ratchet structure is its asymmetric tunnelling barrier. Because the particle tunnelling depends not only on the height but also the shape of the barrier (unlike the classical regime) a net current flow will adjust and its direction strongly depends on the energy distribution of considered particles at given temperature. We are investigating current transport through ratchet structures on GaAs/AlGaAs heterostructures using surface acoustic waves at different temperatures. We examine the behaviour of the driven electrons due to changing the dimensionality of the 2-dimensional electron gas to 1D (nanowires) or 0D (quantum dots) by applying potential on in-plane gates. Because of the built-in broken centrosymmetry of ratchet structures the change of dimensionality has a pronounced effect on the induced net current. We present our initial results and current status of our research.