Rapid collapse of spin waves in non-uniform phases of the second Landau level

TL;DR

This study uses resonant light scattering to investigate spin excitations in the second Landau level, revealing rapid spin wave collapse, loss of polarization, and domain formation in quantum Hall states at various filling factors.

Contribution

It uncovers the collapse of spin waves and the emergence of domain structures in non-uniform phases of the second Landau level, highlighting new spin dynamics in these quantum states.

Findings

Spin wave intensity collapses at lower filling factors.

Emergence of low-lying excitations near ν=8/3 and 5/2.

Formation of domain structures in quantum fluids for ν<3.

Abstract

The spin degree of freedom in quantum phases of the second Landau level is probed by resonant light scattering. The long wavelength spin wave, which monitors the degree of spin polarization, is at the Zeeman energy in the fully spin-polarized state at $\nu$=3. At lower filling factors the intensity of the Zeeman mode collapses indicating loss of polarization. A novel continuum of low-lying excitations emerges that dominates near $\nu$=8/3 and $\nu$=5/2. Resonant Rayleigh scattering reveals that quantum fluids for $\nu<3$ break up into robust domain structures. While the state at $\nu$=5/2 is considered to be fully polarized, these results reveal unprecedented roles for spin degrees of freedom.