Electromagnetic absorption of light in superconducting Kondo alloys and superconductini alloys with strong electron —magnetic-impurity interaction

Abstract

E}ectro~agnetic absorption of light in superconducting Kondo alloys and in superconducting alloys with strong electron —magnetic-impurity interaction is discussed without recourse to the quasiparticle approximation. The electromagnetic (em) absorption of light defined in terms of Shiba-Rusinov equilibrium one-particle Green's functions is examined in the limit of small momentum transfer (London limit) and in the Eliashberg approximation of neglecting the momentum dependence of the electronic self-energy. For the specific case of the Fe-In alloy numerical calculations have been made for the ratio of em absorption in the superconducting and normal states as a function of reduced frequency and temperature for different impurity concentrations.