Correlation effects obtained from optical spectra of Fe-pnictides using an extended Drude-Lorentz model analysis

TL;DR

This paper introduces an extended Drude-Lorentz model to analyze optical spectra of Fe-pnictides, enabling extraction of electron-boson spectral densities and understanding doping effects in high-temperature superconductors.

Contribution

The paper presents a novel extended Drude-Lorentz model that incorporates pseudogap effects for analyzing optical spectra of correlated electron systems.

Findings

Electron-boson spectral densities vary with doping levels.

The model successfully includes pseudogap effects.

Application to K-doped BaFe2As2 reveals doping-dependent spectral features.

Abstract

We introduce an analysis model, an extended Drude-Lorentz model, and apply it to Fe-pnictide systems to extract their electron-boson spectral density functions (or correlation spectra). The extended Drude-Lorentz model consists of an extended Drude mode for describing correlated charge carriers and Lorentz modes for interband transitions. The extended Drude mode can be obtained by a reverse process starting from the electron-boson spectral density function and extending to the optical self-energy and, eventually, to the optical conductivity. Using the extended Drude-Lorentz model, we obtained the electron-boson spectral density functions of K-doped BaFe$_2$As$_2$ (Ba-122) at four different doping levels. We discuss the doping-dependent properties of the electron-boson spectral density function of K-doped Ba-122. We also can include pseudogap effects in the model using this approach. Therefore, this approach is very helpful for understanding and analyzing measured optical spectra of strongly correlation electron systems, including high-temperature superconductors (cuprates and Fe-pnictides).