EFFECT OF TRANSITION METAL IMPURITIES ON THE SUPERCONDUCTING CRITICAL TEMPERATURE. ROLE OF THE s-d COULOMB INTERACTION.

A study is made of the effect of the s-d Coulomb interaction on the superconducting temperature T//c of alloys with a low concentration of nonmagnetic transition metal impurities. The strong interatomic repulsion of electrons with opposite spins is treated exactly and the s-d Coulomb interaction is taken into account in the parquet approximation in the limit GAMMA / epsilon VM LS TH 1, mu VM LS TH 1, and mu ln omega //p/ epsilon similar 1, where GAMMA is the width of the impurity level; mu is the s-d Coulomb interaction constant; and omega //p is the plasma frequency of conduction electrons. It is shown that, in this limit, the s-d Coulomb interaction leads to a lowering of T//c. The change in T//c is calculated in an approximation linear in the impurity concentration.