Hyperfine-controlled domain-wall motion observed in real space and time

TL;DR

This study visualizes magnetic domain-wall motion in a quantum Hall system, revealing nuclear spin influence on propagation speed and suggesting spin interactions as underlying mechanisms.

Contribution

It provides real-space, real-time imaging of domain-wall dynamics in a fractional quantum Hall system, highlighting nuclear spin effects on domain motion.

Findings

Propagation is opposite to electron flow direction.

Nuclear polarization affects domain-wall velocity.

Spin interactions likely govern the observed phenomena.

Abstract

We perform real-space imaging of propagating magnetic domains in the fractional quantum Hall system using spin-sensitive photoluminescence microscopy. The propagation is continuous and proceeds in the direction of the conventional current, i.e. opposite to the electron flow direction. The mechanism of motion is shown to be connected to polarized nuclear spins around the domain walls. The propagation velocity increases when nuclei are depolarized, and decreases when the source-drain current generating this nuclear polarization is increased. We discuss how these phenomena may arise from spin interactions along the domain walls.