Non-Fermi liquid behavior in a fluctuating valence system, the filled skutterudite compound CeRu_{4}As_{12}

TL;DR

This study investigates non-Fermi liquid behavior in the skutterudite compound CeRu4As12, revealing unusual low-temperature electrical and thermodynamic properties linked to valence fluctuations rather than Kondo effects.

Contribution

It provides evidence that NFL behavior in CeRu4As12 arises from valence fluctuations, not Kondo lattice physics, offering new insights into correlated electron systems.

Findings

Electrical resistivity follows T^{1.4} at low T

Specific heat and susceptibility show divergence behaviors

Thermoelectric power deviates from typical Ce systems

Abstract

Electrical resistivity $\rho$, specific heat C, and magnetic susceptibility $\chi$ measurements made on the filled skutterudite CeRu_4As_{12} reveal non-Fermi liquid (NFL) T - dependences at low T, i.e., $\rho$(T) $\sim$ T^{1.4} and weak power law or logarithmic divergences in C(T)/T and $\chi$(T). Measurements also show that the T - dependence of the thermoelectric power S(T) deviates from that seen in other Ce systems. The NFL behavior appears to be associated with fluctuations of the Ce valence between 3^+ and 4^+ rather than a typical Kondo lattice scenario that would be appropriate for an integral Ce valence of 3^+.