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 CexLa1-xB6 is discussed.
- 05.30.-d quantum statistical mechanics
- 05.70.Jk Critical point phenomena
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics