Tunable backscattering in quantum Hall systems induced by neighbouring gates

Using focussed ion beam writing we define an in-plane gate (IPG) modified w ith a bay. Biasing this IPG modifies on the one hand the edge potential and on the other hand the bay width. The first effect governs the interchannel scattering, the second one the backscattering in general. We measure the l ongitudinal resistance R-xx(B) for different gate voltages VG(ate). In the quantum regime both effects are responsible for an increased dependence of the R-xx(x)-peaks and especially of the neighbouring spin-split maxima rati o on V-Gate compared to a simple IPG. A structure with a longer slit realiz ed with two neighbouring IPGs is used to examine the backscattering in the bay region. (C) 2000 Elsevier Science B.V. All rights reserved.