Individual scatterers as microscopic origin of equilibration between spin-polarized edge channels in the quantum Hall regime

We have studied the equilibration between spin-polarized edge states over a distance comparable to the equilibration length, and find fingerprints of the edge state coupling as a function of a gate voltage on top of the edge channels under study. They are interpreted as the consequence of shifting the edge states in energy and space with the gate voltage, thus changing the configuration of individual scatterers that induce spin-flip scattering. In order to quantify this interpretation, the amplitude and period of these resistance fingerprints are related to the average properties of the spin-flip scattering centers using a simple model. Within this model, we find characteristic numbers for individual scatterers. Most strikingly, their average scattering strength lies between those of quantum scatterers and Drude scatterers in all our samples.