Cyclotron spin-flip excitations in a \nu=1/3 quantum Hall ferromagnet

TL;DR

This paper reports the discovery of a new cyclotron spin-flip excitation in a =1/3 quantum Hall ferromagnet, revealing deviations from theoretical predictions and highlighting the role of double-exciton effects.

Contribution

It introduces a novel cyclotron spin-flip mode in a =1/3 quantum Hall system and analyzes the impact of double-exciton corrections on its energy.

Findings

The excitation energy peaks at =1/3, indicating ferromagnetic behavior.

Observed energies exceed single-mode approximation predictions.

Double-exciton effects are significant in understanding the excitation energy.

Abstract

Inelastic light scattering spectroscopy around the \nu=1/3 filling discloses a novel type of cyclotron spin-flip excitation in a quantum Hall system in addition to the excitations previously studied. The excitation energy of the observed mode follows qualitatively the degree of electron spin polarization, reaching a maximum value at \nu=1/3 and thus characterizing it as a \nu=1/3 ferromagnet eigenmode. Its absolute energy substantially exceeds the theoretical prediction obtained within the renowned single-mode approximation. Double-exciton corrections neglected utilizing the single-mode approach are evaluated within the framework of the excitonic representation and are inferred to be responsible for the observed effect.