Extra Spin-Wave mode in Quantum Hall systems. Beyond the Skyrmion Limit

TL;DR

This paper reports the discovery of a new spin mode in quantum Hall systems near odd filling factors, indicating complex magnetic order beyond Skyrmion excitations, with experimental evidence of a zero-energy mode coupling to spin-excitons.

Contribution

It reveals a previously unobserved spin mode in quantum Hall systems that exists outside the Skyrmion limit, suggesting new magnetic phases at partial Landau level fillings.

Findings

Discovery of a new spin mode near odd filling factors.

Evidence of nontrivial magnetic order beyond Skyrmion crystals.

Coupling of the new mode to spin-excitons.

Abstract

We report on the observation of a new spin mode in a quantum Hall system in the vicinity of odd electron filling factors under experimental conditions excluding the possibility of Skyrmion excitations. The new mode having presumably zero energy at odd filling factors emerges at small deviations from odd filling factors and couples to the spin-exciton. The existence of an extra spin mode assumes a nontrivial magnetic order at partial fillings of Landau levels surrounding quantum Hall ferromagnets other then the Skyrmion crystal.