Spatial variations of the order parameter in superconductors containing a magnetic impurity

The spatial variation of the superconductor order parameter in the presence of a classical spin has been analyzed by solving self-consistently the Gorkov equation for the one-particle Green's function. In the vicinity of the impurity the deviations from the bulk pair potential Δ is of the form ΔA(T)sin²kFr(kFr)², where $A(T)$ is a temperature-dependent factor. At large distances from the impurity, rξ₀ (ξ₀ is the superconductor coherence length at zero temperature), Δ(r) varies like 1/r near the transition temperature, as is expected from the Ginzburg-Landau theory. At low temperatures the spatial dependence is oscillatory and decreases as 1r³.