Orbital Kondo Effect in Ce_xLa_(1-x)B₆: Scaling Analysis

Peculiarity of the Kondo effect in Ce$_x$La$_{1-x}$B$_6$ is investigated on the basis of the scaling equations up to third order. For the case where the $f^1$-$f^2$ charge fluctuation enters in addition to the $f^1$-$f^0$ one, the effective exchange interaction becomes anisotropic with respect to the orbital pseudospins which represent the two different orbitals in the $\Gamma_8$ ground state. Because of different characteristic energies for electric and magnetic tensors, scaling with the single Kondo temperature does not apply to physical quantities such as the resistivity and magnetic susceptibility. Possibility of a bizzare phase is pointed out where the RKKY interaction leads to the spin ordering without orbital ordering. This phase serves as a candidate of the phase IV which is observed to be isotropic magnetically.