NONEQUILIBRIUM BEHAVIOR OF SPIN-RESOLVED QUANTUM TRANSPORT IN TILTED MAGNETIC-FIELDS

We investigate the coupling between edge and bulk states in GaAs/GaAlA s quantum Hall conductors with different lateral geometry by analysing the non-ohmic magnetoresistance in quantizing magnetic fields. By til ting the 2DES of the sample in situ with respect to the magnetic field direction, the spin splitting energy is changed with respect to the c yclotron energy. The resulting change of the spatial separation betwee n edge and bulk channels is detected experimentally by changes of the corresponding Shubnikov-de Haas (SdH) peak heights and their current d ependences which allows us to evaluate the equilibration length lambda characterizing the edge-to-bulk scattering. The angular dependences o f lambda obtained experimentally for the different uppermost bulk quan tum levels are compared with model calculations using different assump tions concerning the shape of the confining potential and the dominant scattering process. The assumption of a parabolic confinement potenti al cannot explain the experimental data consistently for all filling f actors. In contrast, a good agreement of measured and calculated data can be obtained within the recently developed picture of alternating c ompressible and incompressible strips near the sample edge. The data s uggest a dominance of single scattering events at short-range scattere rs.