Direct test of composite fermion model in quantum Hall systems

TL;DR

This paper proposes experimental methods using neutron and Raman scattering to measure the composite fermion parameter in quantum Hall systems, and identifies the spin correlation function as an order parameter for spin transitions.

Contribution

It introduces a direct experimental approach to determine the composite fermion filling factor and highlights the role of spin correlation functions as an order parameter.

Findings

Neutron and Raman scattering can measure composite fermion parameters.

Spin correlation functions serve as order parameters in spin transitions.

Partially polarized or unpolarized states are optimal for measurements.

Abstract

We show that neutron scattering and Raman scattering experiments can unambiguously determine a composite fermion parameter, viz., the effective number of Landau Levels filled by the composite fermions. For this purpose, one needs partially polarized or more preferably unpolarized quantum Hall states. We further find that spin correlation function acts as an order parameter in the spin transition.