We find that a bilayer of semiconductors emits a new Goldstone quasiparticle when Landau levels in the layers are half filled. The emission of the new quasiparticle is associated with the divergence in the energy of the system characteristic of a phase transition. There is a Bose condensation of the pairs of quasiparticles in which one electron has spin up and the other down but the orbital magnetic quantum number is very large so that the spin singlet is very different from the Cooper pairs.
@article{arxiv.cond-mat/0106445,
title = {A new phase in the bilayers of semiconductors in quantum Hall effect},
author = {Keshav N. Shrivastava},
journal= {arXiv preprint arXiv:cond-mat/0106445},
year = {2007}
}