We experimentally demonstrate, for the first time, formation of point-like topological defects in the edge state structure in the quantum Hall effect regime. By using of a selective population technique, we investigate equilibration processes between the edge states in bilayer electron structures with a high tunnelling rate between layers. Unexpected flattening of the I-V curves in perpendicular magnetic field at a specific filling factor combination and the recovery of the conventional nonlinear I-V characteristics in tilted fields give a strong evidence for the existence of topological defects.
@article{arxiv.cond-mat/0503478,
title = {Topological defects in the edge state structure in a bilayer electron system},
author = {E. V. Deviatov and V. T. Dolgopolov and A. Wurtz and A. Lorke and A. Wixforth and W. Wegscheider and K. L. Campman and A. C. Gossard},
journal= {arXiv preprint arXiv:cond-mat/0503478},
year = {2009}
}