Magnetic Excitation and Transport Coefficients of the Impurity Anderson Model -Comparison between the 2-Fold and 4-Fold Models

The single-particle and the magnetic excitation spectra at finite temperatures, and the transport coefficients are calculated for the impurity Anderson Hamiltonian by using the numerical renormalization group method. The results for the 2-fold and 4-fold degenerate models are compared. The magnetic excitation spectra show the similar temperature dependence when the models have the same occupation number ratio to the degeneracy number. But for the single-particle excitation and the transport coefficients, the similarity is limited to very low temperatures. The numerical results of the transport coefficients for the 4-fold model agree with the experimental results for dilute Ce ion in LaB₆.