Abstract
We present a self-consistent theory of Kondo impurities in gapless unconventional superconductors valid in the Fermi-liquid regime T≲. The impurity degrees of freedom are treated using the large-N slave-boson technique, leading to tractable equations describing the interplay between the Kondo effect and superconductivity. We show that for a single impurity in a superconductor with density of states N(ω)∼‖ω, there exists a critical coupling below which the Kondo effect does not occur. However, for r≤1 or N=2 any finite concentration of impurities drives →0. The theory provides microscopic support for phenomenological models of resonant impurity scattering in heavy-fermion systems.
- Received 17 June 1992
DOI:https://doi.org/10.1103/PhysRevB.46.9274
©1992 American Physical Society