Elementary excitation for the orbitally degenerate Anderson model at finite temperatures - art. no. 024407

The elementary excitation for the orbitally degenerate Anderson model at fi nite temperatures is studied using the Bethe ansatz solution. The formulati on of the elementary excitation at finite temperatures is based on the meth od which was first developed by Yang and Yang for the one-dimensional boson system with the delta -function type interaction. The expressions of the e lementary excitation energy for the spin and the charge degrees of freedom are derived. Using the obtained expressions, the spin and the charge excita tion spectrums are calculated numerically. With decreasing temperature, the peak structure grows in the spin excitation spectrum, whereas the weight a round the impurity level increases in the charge excitation spectrum, below the temperature corresponding to the characteristic energy scale of the sy stem. The crystalline-field effects on the elementary excitation spectrums are investigated in the Kondo regime, and the results are discussed in conn ection with the difference in the Kondo temperature. The relation between t he obtained results and the thermodynamic quantity of the orbitally degener ate Anderson model is also discussed.