Searches for Skyrmions in the Limit of Zero g-Factor

TL;DR

This study investigates the behavior of Skyrmions in quantum Hall states at zero g-factor by measuring energy gaps under varying Zeeman energies, revealing Skyrmionic excitations at specific filling factors.

Contribution

It provides experimental evidence of Skyrmion excitations at v=1 and 3 in the limit of zero g-factor through pressure-tuned energy gap measurements.

Findings

Energy gaps decrease with pressure at v=1

Skyrmions appear at low Zeeman energy

Minimum gap width shrinks as g-factor approaches zero

Abstract

Energy gaps have been measured for the ferromagnetic quantum Hall effect states at v=1 and 3 in GaAs/GaAlAs heterojunctions as a function of Zeeman energy, which is reduced to zero by applying hydrostatic pressures of up to 20kbar. At large Zeeman energy the gaps are consistent with spin wave excitations. For a low density sample the gap at v=1 decreases with increasing pressure and reaches a minimum when the g-factor vanishes. At small Zeeman energy the excitation appears to consist of a large number of reversed spins and may be interpreted as a Skyrmion. The data also suggest Skyrmionic excitations take place at v=3. The width of the minimum at v=1 is found to decrease as the g-factor is reduced in a similar way for all samples.