SELECTION-RULES FOR 2-CHANNEL KONDO MODELS OF U-4+ AND CE-3+ IONS IN METALS

Symmetry-based selection rules are developed providing minimal criteria for the existence of two-channel Kondo interactions between conduction electrons and the low energy degrees of freedom on U4+ and Ce3+ in a metal host, assuming that the underlying microscopics are regulated by the Anderson Hamiltonian. An additional dynamic selection rule is imposed on Ce3+ ions. The selection rules restrict the two-channel quadrupolar Kondo effect to U4+ ions in cubic, tetragonal and hexagonal symmetry. For hexagonal and tetragonal symmetry, the Kondo effect for a U4+ ion will always be quadrupolar. The selection rules for Ce3+ ions restrict the two-channel magnetic Kondo effect to one of three possible doublet ionic ground states in hexagonal symmetry and the lone doublet ionic ground state in cubic symmetry. The dynamical selection rule apparently excludes two-channel Kondo behavior for Yb3+ ions.