COMPETITION BETWEEN HUND-RULE COUPLING AND KONDO EFFECT

We investigate a problem about the competition between the hybridizati on and the Hund-rule coupling by applying the Wilson numerical renorma lization-group method to the extended Kondo model where the impurity s pin interacts via the Hund-rule coupling, with an extra spin which is isolated from the conduction electrons. It is shown that the Hund-rule coupling is an irrelevant perturbation against the strong coupling fi xed point. However, the Hund-rule coupling decreases the characteristi c energy T-K drastically to the lower side and the irrelevant operator , which describes the low energy physics, takes a form of ferromagneti c exchange interaction between the extra spin and the Kondo resonance states because of the existence of the Hund-rule coupling.