Calculation of optical conductivity, resistivity and thermopower of filled skutterudite CeRu4Sb12 based on a realistic tight-binding model with strong correlation

摘要

The filled-skutterudite compound CcRu(4)Sb(12) shows a pseudogap structure for the optical conductivity spectra similar to the Kondo insulators; however, it exhibits metallic behavior below 80 K. The resistivity shows a large peak at 80 K, and the Seebeck coefficient is positive and also shows a large peak at nearly the same temperature. In order to explain these features, a simplified tight-binding model, which captures the essential features of the band calculation, is proposed. Using this model and introducing the correlation effect within the framework of the dynamical mean field approximation and iterative perturbation theory, the temperature dependences of the optical conductivity. resistivity and Seebeck coefficient arc calculated; these are expected to explain the experiments.