Transport gap in a nu=1/3 quantum Hall system: a probe for skyrmions

TL;DR

This study investigates the transport gap in a ν=1/3 fractional quantum Hall system, revealing a transition from antiskyrmion excitations to spinless states with increasing magnetic field, supported by experimental and theoretical analysis.

Contribution

It combines experimental measurements with exact diagonalization calculations to identify skyrmion excitations and their crossover to spinless states in the quantum Hall regime.

Findings

Identification of antiskyrmions at low magnetic fields

Crossover to spinless excitations at higher fields

Good agreement between theory and experiment when including Landau level mixing

Abstract

The dependence of the activated gap on magnetic field is studied for the fractional filling factor~1/3. By comparing the experimental results with results from exact diagonalization calculations we are able to identify the excitation of a small antiskyrmion in the low-field regime and a cross-over to spinless excitations at higher magnetic fields. The effect of sample quality is studied. On the side of the theory, comparison between different geometries (torus and sphere) and different sizes is carried out. Under inclusion of Landau level mixing and finite thickness, we obtain a good agreement between calculated energies and experimental results.