Correlation Effects on Optical Conductivity of FeSi

TL;DR

This paper investigates how electron correlation influences the optical conductivity of FeSi using a two-band Hubbard model and self-consistent perturbation theory, successfully reproducing experimental features and explaining peak shifts.

Contribution

It introduces a combined theoretical approach to study correlation effects on optical properties of FeSi, aligning well with experimental observations.

Findings

Correlation effects shift the optical conductivity peak to lower energies.

The model reproduces experimental optical spectra semiquantitatively.

Electron correlations significantly modify the density of states.

Abstract

Effects of electron correlation in FeSi are studied in terms of the two-band Hubbard model with the density of states obtained from the band calculation. Using the self-consistent second-order perturbation theory combined with the local approximation, the correlation effects are investigated on the density of states and the optical conductivity spectrum, which are found to reproduce the experiments done by Damascelli et al. semiquantitatively. It is also found that the peak at the gap edge shifts to lower energy region by correlation effects, as is seen in the experiments.