IMPURITY-DOPING IN HIGH-T-C SUPERCONDUCTORS - ANDERSON LOCALIZATION VERSUS INTERACTION EFFECT

A perturbation approach is adopted to deal with localization in a diso rdered metal. It is shown that in the case of a given impurity potenti al a small disorder leads to localization in 2D as well as in 1D, and causes the weak localization in 3D. As a result, in the system the loc alized magnetic moments appear and the ferromagnetic phase transition can happen. In contrast, in the case of the screened impurity potentia l (interacting electrons) the disorder effect on polarizablility can s ignificantly be suppressed by the Coulomb vertex corrections to the im purity vertex as shown.