Regensburg 2000 – scientific programme

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HL: Halbleiterphysik

HL 17: Symposium: Der Quanten-Hall-Effekt wird 20 (II)

HL 17.6: Talk

Tuesday, March 28, 2000, 18:00–18:15, H15

A New Network Model for the Integer Quantum Hall Effect — •Josef Oswald and Alois Homer — Dept. of Physics, University of Leoben, Franz Josef Str.18, A-8700 Leoben, Austria

Recently we have extended the Landauer- Buttiker formalism in order to include also the presence of a dissipative bulk current[1] and use it now in a novel network approach for bulk transport. In this presentation we will show, that our model allows to calculate the resistance components Rxx and Rxy as well as the potential distribution in the bulk for for the IQHE for almost any sample geometry. It allows us to define realistic sample structures by shaping the lateral carrier density profile to e.g. a Hall bar with realistic contact arms and side depletion zones. Furthermore it is possible to model in-homogeneities like introduced by a gate electrode across the Hall bar. Ryan et al.[2] performed a systematic experimental study of the effect of a gate electrode across a Hall bar and obtained a complete set of Rxx-data from sweeping the magnetic field at quite a number of different gate voltages ranging from deep depletion to accumulation. That experimental data contain a lot of features, which are quantitatively reproduced by our model calculations.

Supported by FWF-Austria (Project P10510NAW) and the OENB (Project 6566)

[1] J.Oswald, G.Span, F.Kuchar, Phys.Rev.B58, 15401-15404 (1998)

[2] R.M.Ryan, N.F.Deutscher and D.K.Ferry, Phys.Rev.B48, 8840 (1993)