Incoherent non-Fermi liquid scattering in a Kondo lattice

TL;DR

This paper investigates the origin of T-linear resistivity in CeCoIn5, revealing its dependence on the f-electron configuration of substituted rare-earth ions and linking it to incoherent scattering centers in the Kondo lattice.

Contribution

It demonstrates that T-linear scattering in CeCoIn5 is controlled by the nature of incoherent scattering centers, advancing understanding of quantum criticality in heavy-fermion systems.

Findings

T-linear resistivity depends on the f-electron configuration of R ions.

Cooper-pair breaking and Kondo coherence are unaffected by R substitution.

Incoherent scattering centers are key to quantum critical behavior.

Abstract

One of the most notorious non-Fermi liquid properties of both archetypal heavy-fermion systems [1-4] and the high-Tc copper oxide superconductors [5] is an electrical resistivity that evolves linearly with temperature, T. In the heavy-fermion superconductor CeCoIn5 [5], this linear behaviour was one of the first indications of the presence of a zero-temperature instability, or quantum critical point. Here, we report the observation of a unique control parameter of T-linear scattering in CeCoIn5, found through systematic chemical substitutions of both magnetic and non-magnetic rare-earth, R, ions into the Ce sub-lattice. We find that the evolution of inelastic scattering in Ce1-xRxCoIn5 is strongly dependent on the f-electron configuration of the R ion, whereas two other key properties -- Cooper-pair breaking and Kondo-lattice coherence -- are not. Thus, T-linear resistivity in CeCoIn5 is intimately related to the nature of incoherent scattering centers in the Kondo lattice, which provides insight into the anomalous scattering rate synonymous with quantum criticality [7].