Spin polarization of Quantum Hall states for filling factors 1 < v < 2 measured with microcavity polaritons

TL;DR

This study investigates spin polarization in quantum Hall states with filling factors between 1 and 2 using microcavity polaritons, revealing full polarization at v=1 and behaviors consistent with composite fermion models.

Contribution

It provides new experimental measurements of spin polarization in this regime, including optical and temperature dependence, supporting the composite fermion theory.

Findings

Full spin polarization at v=1 with Skyrmion-related depolarization

Depolarization of v=4/3, 8/5 states and repolarization of v=5/3 state

Evidence of non-linear optical effects in the v=1 regime

Abstract

Spin polarization measurements were performed in three 2D Electron Gases in GaAs with densities n = 9.1, 7.2 and 6.5 x10^10 cm-2, in the quantum Hall regime. Full spin polarization at v = 1 surrounded by rapid depolarization due to Skyrmion formation was observed in all devices, consistent with past measurements. Depolarization of the v = 4/3, 8/5 states and repolarization of the v = 5/3 state was also measured, in remarkable agreement with a non-interacting, disorder-free Composite Fermion model. Optical power and temperature dependent measurements of the v = 1 state suggest a regime of non-linear optics.