2010/07/12 by Egor Babaev, Johan Carlstrom
Physics and Astronomy · #cond-mat.supr-con
paper · pdf · doi:10.1016/j.physc.2010.02.025
published as Physica C 470 717-721 (2010) proceedings of the Vortex VI conference · A talk given at the Vortex VI conference on 17 September 2009, Rhodes, Greece
arxiv created 2010/07/12 · arxiv updated 2015/05/19
In the usual Ginzburg-Landau theory the critical value of the ratio of two fundamental length scales in the thery κc=1/√(2) separates regimes of type-I and type-II superconductivity. The latter regime possess thermodynamically stable vortex excitations which interact with each other repulsively and tend to form vortex lattices. It was shown in [5] that this dichotomy in broken in U(1)xU(1) Ginzburg-Landau models which possess three fundamental length scales which results in the existence of a distinct phase with vortex excitations which interact attractively at large length scales and repulsively at shorter distances. Here we briefly review these results in particular discussing the role of interband Josephson coupling and the case where only one band is superconducting while superconductivity in another band is induced by interband proximity effect. The report is partially based on E. Babaev, J. Carlstrom, J. M. Speight arXiv:0910.1607.