SPATIAL DEPENDENCE OF THE SUPERCONDUCTING ORDER-PARAMETER NEAR AN ANDERSON IMPURITY

We develop a general theory for the local environment of a magnetic impurity in a superconductor, using an Anderson model to describe the impurity. We can thus cover many regimes (i.e, Kondo, mixed valence) of physical interest. A general formula expressing the perturbed order parameter, deltaDELTA(q), in terms of the impurity t matrix is derived; this formula is then used to derive a simple expression, valid as T --> T(c), relating the total volume integral of deltaDELTA(r) to the change in T(c) with impurity concentration. Finally, explicit curves for deltaDELTA(r) are computed for the Hartree-Fock limit.