Large Skyrmions in an Al(0.13)Ga(0.87)As Quantum Well

TL;DR

This study investigates large skyrmions in a specific quantum well by measuring energy gaps at various tilt angles, revealing unusually large skyrmionic excitations and discrepancies with theoretical models.

Contribution

It reports the observation of the largest skyrmions to date in a quantum well and compares experimental results with Hartree-Fock calculations, highlighting their limitations.

Findings

Skyrmions with ~50 spins observed

Energy gaps are smaller than Hartree-Fock predictions

Large skyrmions consistent with experimental data

Abstract

We report tilted-field magnetotransport measurements of two-dimensional electron systems in a 200 Angstrom-wide Al(0.13)Ga(0.87)As quantum well. We extract the energy gap for the quantum Hall state at Landau level filling \nu =1 as a function of the tilt angle. The relatively small effective Lande g-factor (g ~ 0.043) of the structure leads to skyrmionic excitations composed of the largest number of spins yet reported (s ~ 50). Although consistent with the skyrmion size observed, Hartree-Fock calculations, even after corrections, significantly overestimate the energy gaps over the entire range of our data.