Observation of exchange Coulomb interactions in the quantum Hall state at nu=3

TL;DR

This study measures Coulomb exchange interactions in the nu=3 quantum Hall state using resonant inelastic light scattering, revealing strong mode repulsion and agreement with Hartree-Fock theory.

Contribution

It provides the first experimental observation of exchange Coulomb interactions at nu=3, linking collective excitations to inter-Landau level spin-flip transitions.

Findings

Strong repulsion between spin-flip modes observed

Exchange contributions comparable to nu=1 state

Good agreement with Hartree-Fock calculations

Abstract

Coulomb exchange interactions of electrons in the nu=3 quantum Hall state are determined from two inter-Landau level spin-flip excitations measured by resonant inelastic light scattering. The two coupled collective excitations are linked to inter-Landau level spin-flip transitions arising from the N=0 and N=1 Landau levels. The strong repulsion between the two spin-flip modes in the long-wave limit is clearly manifested in spectra displaying Coulomb exchange contributions that are comparable to the exchange energy for the quantum Hall state at nu=1. Theoretical calculations within the Hartree-Fock approximation are in a good agreement with measured energies of spin-flip collective excitations.