Perturbative renormalization of multi-channel Kondo-type models

Abstract:

The poor man's scaling is extended to higher order by the use of the open-shell Rayleigh-Schrödinger perturbation theory. A generalized Kondo-type model with the SU(n)SU(m) symmetry is proposed and renormalized to the third order. It is shown that the model has both local Fermi-liquid and non-Fermi-liquid fixed points, and that the latter becomes unstable in the special case of n=m=2. Possible relevance of the model to the newly found phase IV in Ce_xLa_1-xB₆ is discussed.