ON THE MULTICHANNEL KONDO MODEL

A detailed and comprehensive study of the one-impurity multichannel Ko ndo model is presented. In the limit of a large number of conduction e lectron channels k >> 1, the low-low-energy fixed point is accessible to a renormalization group improved perturbative expansion in 1/k. Thi s straightforward approach enables us to examine the scaling, thermody namics and dynamical response functions in great detail and make clear the following features: (i) the criticality of the fixed point, (ii) the universal non-integer degeneracy, and (iii) that the compensating spin cloud has a spatial extent of the order of one lattice spacing.