We discuss the behaviour of a quantum Hall system when two Landau levels with opposite spin and combined filling factor near unity are brought into energetic coincidence using an in-plane component of magnetic field. We focus on the interpretation of recent experiments under these conditions [Zeitler et al, Phys. Rev. Lett. 86, 866 (2001); Pan et al, Phys. Rev. B 64, 121305 (2001)], in which a large resistance anisotropy develops at low temperatures. Modelling the systems involved as Ising quantum Hall ferromagnets, we suggest that this transport anisotropy reflects domain formation induced by a random field arising from isotropic sample surface roughness.
@article{arxiv.cond-mat/0208024,
title = {Quantum Hall ferromagnets, cooperative transport anisotropy, and the random field Ising model},
author = {J. T. Chalker and D. G. Polyakov and F. Evers and A. D. Mirlin and P. Woelfle},
journal= {arXiv preprint arXiv:cond-mat/0208024},
year = {2011}
}