Non-local polarization feedback in a fractional quantum Hall ferromagnet

TL;DR

This paper reports a non-local feedback effect between nuclear polarization and electronic domains in a fractional quantum Hall system, leading to memristive behavior and offering new insights into edge state dynamics.

Contribution

It introduces a novel non-local polarization feedback mechanism in fractional quantum Hall ferromagnets, linking nuclear and electronic domain interactions with memristive electronic transport.

Findings

Observation of memristive behavior in quantum point contact transport

Identification of non-local nuclear-electronic feedback effects

Proposal of a model explaining oscillatory transport features

Abstract

In a quantum Hall ferromagnet, the spin polarization of the two-dimensional electron system can be dynamically transferred to nuclear spins in its vicinity through the hyperfine interaction. The resulting nuclear field typically acts back locally, modifying the local electronic Zeeman energy. Here we report a non-local effect arising from the interplay between nuclear polarization and the spatial structure of electronic domains in a $\nu=2/3$ fractional quantum Hall state. In our experiments, we use a quantum point contact to locally control and probe the domain structure of different spin configurations emerging at the spin phase transition. Feedback between nuclear and electronic degrees of freedom gives rise to memristive behavior, where electronic transport through the quantum point contact depends on the history of current flow. We propose a model for this effect which suggests a novel route to studying edge states in fractional quantum Hall systems and may account for so-far unexplained oscillatory electronic-transport features observed in previous studies.