Realization of Heavy Local Fermi Liquid and Non-Fermi Liquid in f² Crystalline-Electric-Field Singlet–Triplet Configuration

Abstract

Using the numerical renormalization group method, we investigate an extended Anderson model, in which correlated electrons with the Γ₁ (singlet)–Γ₄ (triplet) f² crystalline-electric-field (CEF) configuration hybridize with conduction electrons of Γ₇ (doublet) and Γ₈ (quartet) under cubic O_h symmetry, from a strong spin–orbit interaction limit. For the case of the parameters relevant to PrFe₄P₁₂, the system is under competition between the CEF singlet fixed point and the multichannel Kondo non-Fermi liquid fixed point arising from the quadrupolar coupling between the impurity with pseudospin 1 and the conduction electron with pseudospin 3/2 . We consider that this result reveals the origin of the heaviness of the effective mass and non-Fermi liquid behavior of the Pr-based filled skutterudite compounds.