title: Impurities and quantum interference in the chains of YBa2Cu3O6+x.
abstract: Motivated by recent experiments, we study the electronic structure near impurities in the chains of YBa2Cu3O6+x. Using a model of proximity induced chain superconductivity, we show that a resonance state in the chain density of states is induced only by a magnetic impurity. The spatial form of the resonance reflects the particle-hole nature of chain superconductivity and therefore distinguishes it from other broken symmetry phases. Because of quantum interference effects between impurities, the chains can undergo a quantum phase transition into a polarized state.
authors.affiliation: Department of Physics, University of Illinois at Chicago, Chicago, Illinois 60607, USA.
authors.forename: Dirk K
authors.initials: DK
authors.lastname: Morr
authors.forename: Alexander V
authors.initials: AV
authors.lastname: Balatsky