Superconducting-Quasiparticle Interface States

Abstract
We describe superconducting-quasiparticle interface states which are produced by a certain class of local potentials at interfaces involving superconductors. These states penetrate at least a coherence distance into the superconductor and arise even when the pair potential is uniform throughout the superconductor. We specifically predict such a state at the interface between an insulating ferromagnet below its Curie temperature and a thin superconductor.