Regensburg 2002 – wissenschaftliches Programm

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HL: Halbleiterphysik

HL 11: Poster 1

HL 11.41: Poster

Montag, 11. März 2002, 17:00–19:30, Poster A

Time-resolved Magnetotransport Measurements in the Quantum Hall Regime — •G. Sukhodub, F. Hohls, and R.J. Haug — Inst. f. Festkörperphys., Uni Hannover, Appelstr. 2, 30167 Hannover

We examine the propagation of an electrical pulse through a two-dimensional electron system (2DES) in the QHE regime with a nanosecond resolution using a box-car technique [1]. Along the higher potential edge we observe a fast pulse propagation with saturation times about ≃100 ns. This can be described in terms of a wave packet of edge magnetoplasmons propagating in the edge region [1]. Measuring at the opposite sample edge we find that the pulse propagates noticeable slower saturating within some 10 ms. The amplitude transmitted to the opposite edge as a function of the magnetic field is strongly correlated with the Shubnikov - de Haas (SdH) oscillations of the magnetoresistance. No signal can be detected in the QHE plateaus.

Considering the sample as a conductor capacitively coupled to the grounded top gate we apply the RC-chain model to the magnetic field dependence of the rise time τ. As the calculated propagation length nearly coincides with the sample width we derive that the pulse propagation to the lower potential edge occurs through the bulk of the sample perpendicular to the edge structure.

[1] G. Ernst et al., Phys. Rev. Lett. 79, 3749 (1997)