Realization of Heavy Local Fermi Liquid and Non-Fermi Liquid in f$^2$ Crystalline-Electric-Field Singlet-Triplet Configuration

TL;DR

This paper uses numerical renormalization group analysis to explore how specific crystalline-electric-field configurations in f$^2$ systems lead to heavy Fermi liquid and non-Fermi liquid behaviors, relevant to Pr-based skutterudites.

Contribution

It demonstrates the coexistence and competition of Fermi liquid and non-Fermi liquid fixed points in an extended Anderson model with f$^2$ CEF configurations under cubic symmetry.

Findings

Identification of competition between CEF singlet and multichannel Kondo fixed points.

Revealing the origin of heavy effective mass in Pr-based compounds.

Explanation of non-Fermi liquid behavior in specific parameter regimes.

Abstract

Using the numerical renormalization group method, we investigate an extended Anderson model, in which correlated electrons with the $\Gamma_1$(singlet)-$\Gamma4$(triplet) f$^2$ crystalline-electric-field (CEF) configuration hybridize with conduction electrons of $\Gamma_7$(doublet) and $\Gamma_8$ (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.