title: Constructive influence of the induced electron pairing on the Kondo state.
abstract: Superconducting order and magnetic impurities are usually detrimental to each other. We show, however, that in nanoscopic objects the induced electron pairing can have constructive influence on the Kondo effect originating from the effective screening interactions. Such situation is possible at low temperatures in the quantum dots placed between the conducting and superconducting reservoirs, where the proximity induced electron pairing cooperates with the correlations amplifying the spin-exchange potential. The emerging Abrikosov-Suhl resonance, which is observable in the Andreev conductance, can be significantly enhanced by increasing the coupling to superconducting lead. We explain this intriguing tendency within the Anderson impurity model using: the generalized Schrieffer-Wolff canonical transformation, the second order perturbative treatment of the Coulomb repulsion, and the nonperturbative numerical renormalization group calculations. We also provide hints for experimental observability of this phenomenon.
authors.affiliation: Institute of Physics, M. Curie Skłodowska University, 20-031 Lublin, Poland.
authors.forename: T
authors.initials: T
authors.lastname: Domański
authors.affiliation: Faculty of Physics, A. Mickiewicz University, ul. Umultowska 85, 61-614 Poznań, Poland.
authors.forename: I
authors.initials: I
authors.lastname: Weymann
authors.affiliation: Institute of Physics, M. Curie Skłodowska University, 20-031 Lublin, Poland.|Institute of Physics, Polish Academy of Sciences, 02-668 Warsaw, Poland.
authors.forename: M
authors.initials: M
authors.lastname: Barańska
authors.affiliation: Faculty of Mathematics and Natural Sciences, University of Rzeszów, 35-310 Rzeszów, Poland.
authors.forename: G
authors.initials: G
authors.lastname: Górski