Exact diagonalization study of domain structure in integer filling factor quantum Hall ferromagnets

TL;DR

This study uses exact diagonalization to analyze the domain structure in integer filling factor quantum Hall ferromagnets, revealing that the ground state is an Ising ferromagnet with domain walls, explaining recent magnetotransport anomalies.

Contribution

It provides a microscopic, exact diagonalization analysis of the domain structure in quantum Hall ferromagnets at integer filling factors, linking theory to recent experimental observations.

Findings

The ground state at coincidence is an Ising quantum Hall ferromagnet.

Low energy excitations are domain wall formations.

Magnetotransport anomalies are explained by domain structures.

Abstract

Opposite spin Landau levels in a quantum well can be brought into coincidence by tilting the magnetic field away from normal orientation. We demonstrate that the magnetotransport anomaly at integer filling factors that was recently discovered by Pan {\it et al} is due to such a coincidence. By performing exact diagonalization calculations using microscopically evaluated effective electron-electron interactions, we are able to establish that the electronic ground state at coincidence is an Ising quantum Hall ferromagnet and that the low energy excitations correspond to the formation of a domain wall.