Electron-phonon interaction in a superconductor with Kondo scattering

TL;DR

This paper investigates how Kondo scattering and localized states in a superconductor with magnetic impurities affect non-equilibrium properties, revealing distinct temperature-dependent kinetic behaviors.

Contribution

It introduces a detailed model of inelastic quasiparticle transitions involving localized states, incorporating deformation potential and spin-lattice coupling effects.

Findings

Localized states significantly alter quasiparticle interactions.

Distinct temperature dependences observed for different inelastic processes.

Processes include trapping, recombination, and pair breaking of quasiparticles.

Abstract

In a superconductor with magnetic impurities, Kondo scattering results in the formation of localized states inside the superconducting gap. We show that inelastic electronic transitions involving quasiparticle scattering into and out of the localized states may result in significant changes in the non equilibrium properties of the superconductor. Using the model of Muller-Hartmann and Zittartz for the extreme dilute limit, and including both deformation potential and spin-lattice coupling we have calculated the rates of such inelastic transitions between continuum and discrete states, and shown that they may greatly modify quasiparticle interactions. The individual processes are: quasiparticle trapping into discrete states, enhanced recombination with localized quasiparticles, and pair breaking and detrapping of localized quasiparticles by sub-gap phonons. We find that all these processes give rise to clearly distinguishable temperature dependences of the kinetic parameters.