Crystal Field Triplets: A New Route to Non-Fermi Liquid Physics

TL;DR

This paper introduces a new model for crystal field triplet ground states with dipolar and quadrupolar couplings, revealing a novel non-Fermi liquid fixed point with distinctive magnetic susceptibility behavior.

Contribution

It is the first study of this model using renormalization group methods, uncovering a new non-Fermi liquid fixed point due to quadrupolar coupling.

Findings

Discovery of a nontrivial non-Fermi liquid fixed point.

Magnetic susceptibility scales as T^{-0.4} at intermediate temperatures.

Relevance to non-Fermi liquid alloy UCu_{5-x}Pd_x.

Abstract

A model for crystal field triplet ground states on rare earth or actinide ions with dipolar and quadrupolar couplings to conduction electrons is studied for the first time with renormalization group methods. The quadrupolar coupling leads to a new nontrivial, non-Fermi liquid fixed point, which survives in an intermediate valence Anderson model. The calculated magnetic susceptibility displays one parameter scaling, going as $T^{-\alpha}$ ($\alpha \approx 0.4$) at intermediate temperatures, reminiscent of the non-Fermi liquid alloy UCu_{5-x}Pd_x.