Abstract
The possibility of singlet-like superconductivity in a hybridized two-band system is investigated. We reformulate the problem in terms of quasi-particle states originating from narrowf-like band and conduction band states. An effective BCS-like Hamiltonian for heavy and light quasi-particles is derived. The stability of these two types of Cooper pairs is studied by using the occupation number of heavy particles as an input parameter. Our results provide strong support for the assumption that in this kind of two-band system a cross-over effect can be observed. For large enough values of the input parameter superconductivity is mainly supported by heavy quasi-particles. By reducing the occupation number superconductivity is taken over by the light quasi-particles. The relevance of the results for heavy-fermion superconductors is discussed.
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Zieliński, J., Entel, P. & Pietruszka, M. Quasi-particle description of cross-over effects in two-band superconductors. Z. Physik B - Condensed Matter 66, 161–166 (1987). https://doi.org/10.1007/BF01311651
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DOI: https://doi.org/10.1007/BF01311651