Electrical and thermal transport properties of intermetallic RCoGe2 (R = Ce and La) compounds.

To investigate the electronic structure of the intermetallic compound CeCoGe2, we performed electrical resistivity (ρ), Seebeck coefficient (S), and thermal conductivity (κ) measurements in a temperature range of 10-300 K. For comparison, the non-magnetic counterpart LaCoGe2 is also studied. It is found that CeCoGe2 exhibits a broad maximum in the S(T) near 75 K, at which the sudden drop in the ρ(T) is observed. Temperature-dependent electrical resistivity and the Seebeck coefficient of CeCoGe2 can be described well by a two-band model, which reveals the signature of Kondo scattering in CeCoGe2. On the other hand, a typical metallic-like behavior is seen in the non-magnetic LaCoGe2 from the ρ(T) and S(T) studies. Analysis of the thermal conductivity indicates that the electronic contribution dominates thermal transport above 100 K in both CeCoGe2 and LaCoGe2. In addition, it is found that the variation in low-temperature lattice thermal conductivity of CeCoGe2 as compared to that of LaCoGe2 is most likely due to the phonon-point-defect scattering.