Light scattering observations of spin reversal excitations in the fractional quantum Hall regime

TL;DR

This study uses resonant inelastic light scattering to explore low-energy excitations in fractional quantum Hall states, revealing details about spin reversal energies and composite fermion interactions.

Contribution

It provides new experimental insights into spin excitations and confirms composite fermion theory predictions in the fractional quantum Hall regime.

Findings

Identification of spin reversed excitations near filling factors 1/3 and 2/5

Determination of spin reversal energies indicating residual interactions

Good agreement between experimental results and composite fermion theory predictions

Abstract

Resonant inelastic light scattering experiments access the low lying excitations of electron liquids in the fractional quantum Hall regime in the range $2/5 \geq \nu \geq 1/3$. Modes associated with changes in the charge and spin degrees of freedom are measured. Spectra of spin reversed excitations at filling factor $\nu \gtrsim 1/3$ and at $\nu \lesssim 2/5$ identify a structure of lowest spin-split Landau levels of composite fermions that is similar to that of electrons. Observations of spin wave excitations enable determinations of energies required to reverse spin. The spin reversal energies obtained from the spectra illustrate the significant residual interactions of composite fermions. At $\nu = 1/3$ energies of spin reversal modes are larger but relatively close to spin conserving excitations that are linked to activated transport. Predictions of composite fermion theory are in good quantitative agreement with experimental results.