Fractional Quantum Hall Effect Measurements at Zero g-Factor

TL;DR

This study measures fractional quantum Hall energy gaps in GaAs/GaAlAs heterojunctions under varying Zeeman energy, revealing spin-like excitations and potential skyrmion formation at zero g-factor.

Contribution

It demonstrates how Zeeman energy influences fractional quantum Hall gaps and identifies spin-related excitations, including possible skyrmions, at zero g-factor.

Findings

Energy gap at v=1/3 decreases with pressure until g-factor sign change

Excitations at small Zeeman energy involve multiple spins, resembling skyrmions

Behavior similar to that at v=1, indicating spin-like excitations

Abstract

Fractional quantum Hall effect energy gaps have been measured in GaAs/GaAlAs heterojunctions as a function of Zeeman energy, which is varied by applying hydrostatic pressure up to 20 kbar. The gap at v=1/3 decreases with pressure until the g-factor changes sign when it again increases. The behavior is similar to that seen at v=1 and shows that excitations from the 1/3 ground state can be spin-like in character. At small Zeeman energy, the excitation appears to consist of 3 spins and may be interpreted as a small composite skyrmion.