Incoherent non-Fermi-liquid scattering in a Kondo lattice

Abstract

One of the most notorious non-Fermi-liquid properties of both archetypal heavy-fermion systems and the high-Tc copper oxide superconductors is an electrical resistivity that evolves linearly (rather than quadratically) with temperature, T. In the heavy-fermion superconductor CeCoIn"5 (ref.6), 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 CeCoIn"5, found through systematic chemical substitutions of both magnetic and non-magnetic rare-earth, R, ions into the Ce sublattice. We find that the evolution of inelastic scattering in Ce(1x)R(x)CoIn"5 is strongly dependent on the f-electron configuration of the R ion, whereas two other key propertiesCooper-pair breaking and Kondo-lattice coherenceare not. Thus, T-linear resistivity in CeCoIn"5 is intimately related to the nature of incoherent scattering centres in the Kondo lattice, which provides insight into the anomalous scattering rate synonymous with quantum criticality. © 2007 Nature Publishing Group.