1997/11/30 by Olivier Parcollet, Antoine Georges, Gabriel Kotliar +2 · 3 citations
Physics and Astronomy · #Physics of Superconductivity and Magnetism #Quantum and electron transport phenomena #Rare-earth and actinide compounds #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.58.3794
39 pages, RevTeX, including 5 figures in encapsulated postscript format
arxiv created 1998/06/09 · openalex publication_date 1998/08/15 · arxiv updated 2009/11/30 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
The multichannel Kondo model with SU(N) spin symmetry and SU(K) channel symmetry is considered. The impurity spin is chosen to transform as an antisymmetric representation of SU(N), corresponding to a fixed number of Abrikosov fermions \ensuremath∑_\ensuremathαf_\ensuremathα^\ifmmode†\else\textdagger\fif_\ensuremathα=Q. For more than one channel (K>1), and all values of N and Q, the model displays non-Fermi behavior associated with the overscreening of the impurity spin. Universal low-temperature thermodynamic and transport properties of this non-Fermi-liquid state are computed using conformal field theory methods. A large-N limit of the model is then considered, in which K/N\ensuremath≡\ensuremathγ and Q/N\ensuremath≡q0 are held fixed. Spectral densities satisfy coupled integral equations in this limit, corresponding to a (time-dependent) saddle point. A low-frequency, low-temperature analysis of these equations reveals universal scaling properties in the variable \ensuremathω/T, in agreement with conformal invariance. The universal scaling form is obtained analytically and used to compute the low-temperature universal properties of the model in the large-N limit, such as the T=0 residual entropy and residual resistivity, and the critical exponents associated with the specific heat and susceptibility. The connections with the ``noncrossing approximation'' and the previous work of Cox and Ruckenstein are discussed.