DEGENERATE ANDERSON IMPURITY MODEL IN THE PRESENCE OF SPIN-ORBIT AND CRYSTAL-FIELD SPLITTING

Using a quantum Monte Carlo technique combined with the method of maxi mum entropy, we calculated the magnetic susceptibility and spectral pr operties of the degenerate single-impurity Anderson model in the prese nce of spin-orbit and crystal-field splitting. At small hybridization and moderate temperatures, the magnetic susceptibility displays a nonu niversal behavior. Under the influence of spin-orbit splitting, the ma gnetic susceptibility decreases due to the quenching of a sixfold-dege nerate state to an effectively doubly degenerate state. The effect of crystal-field splitting on the magnetic susceptibility is less pronoun ced. The temperature dependence of the spectral function changes drama tically under the influence of spin-orbit splitting. In the accessible temperature regime, the central peak at omega similar to 0 decreases with decreasing temperature.