EFFECT OF CORRELATION ON OCCURRENCE OF LOCAL MAGNETIC MOMENTS IN METALS

A new Green's function decoupling scheme has been applied to the problem of how correlation affects the occurrence of local moments in metals. Using Anderson's one orbital model, the decoupling level is above Hartree but presumably too low to include the Kondo effect. The scheme is similar to Hewson's but includes certain energy shifts which make magnetic states more likely to occur. For very weak transfer interaction between the impurity and conduction electrons, both magnetic and nonmagnetic solutions are found. The nonmagnetic state usually has lower energy in agreement with Schrieffer and Mattis and others, but when the intra-atomic Coulomb energy is sufficiently large, the magnetic solution has the lower energy. For strong enough transfer interaction the magnetic solution, of course, disappears. © 1969 The American Institute of Physics.