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

TL;DR

This paper investigates the microscopic origin of equilibration between spin-polarized edge channels in the quantum Hall regime by analyzing individual scatterers and their impact on edge state coupling.

Contribution

It introduces a model linking macroscopic edge state coupling to individual spin-flip scatterers and extracts their characteristic parameters from experimental data.

Findings

Reproducible fluctuations indicate single spin-flip scatterers influence coupling.

Characteristic distances between scatterers are between Drude and quantum scattering lengths.

A model successfully relates microscopic scatterers to macroscopic edge state behavior.

Abstract

The equilibration length between spin-polarized edge states in the Quantum Hall regime is measured as a function of a gate voltage applied to an electrode on top of the edge channels. Reproducible fluctuations in the coupling are observed and interpreted as a mesoscopic fingerprint of single spin-flip scatterers which are turned on and off. A model to analyze macroscopic edge state coupling in terms of individual scatterers is developed, and characteristic values for these scatterers in our samples are extracted. For all samples investigated, the distance between spin-flip scatterers lies between the Drude and the quantum scattering length.