Optical conductivity of filled skutterudites

TL;DR

This paper develops a tight-binding model for Ce-based filled skutterudites to analyze their optical conductivity, emphasizing the significant role of electron correlations in temperature-dependent behavior and gap disappearance.

Contribution

It introduces a simplified tight-binding framework combined with self-consistent perturbation theory to study optical properties of filled skutterudites, highlighting correlation effects.

Findings

Electron correlations significantly influence optical conductivity.

The model reproduces the temperature-induced gap disappearance.

Correlation effects are crucial for accurate optical property descriptions.

Abstract

A simple tight-binding model is constructed for the description of the electronic structure of some Ce-based filled skutterudite compounds showing an energy gap or pseudogap behavior. Assuming band-diagonal electron interactions on this tight-binding model, the optical conductivity spectrum is calculated by applying the second-order self-consistent perturbation theory to treat the electron correlation. The correlation effect is found to be of great importance on the description of the temperature dependence of the optical conductivity. The rapid disappearance of an optical gap with increasing temperature is obtained as observed in the optical experiment for Ce-based filled-skutterudite compounds.