Unorthodox Approach to Realize the Correlation between the Dielectric Constant and Electronic Disorder in Cr-Doped PrFeO3

Abstract

Here, in the present report, an attempt has been made to explore a quantitative correlation between the Urbach energy (EU) and the dielectric constant (ϵ) by using a Bohr-like model for Cr-substituted PrFeO3. In order to quantify the EU and ϵ values, optical absorption spectroscopy, Raman scattering, and dielectric measurements have been carried out. The dielectric experiments suggest a decrease in ϵ values, whereas a systematic increase in the values of EU has been observed with Cr doping. It is shown that EU exhibits inverse square dependence with ϵ (EU ∼1/ϵ2) up to a certain fraction of Cr (<20%), which is found to be consistent with the quantitative relation obtained by the Bohr-like model. The present investigation explores quantitatively the relationship between ϵ and EU, which has significant importance for improving the dielectric and optical properties in strongly correlated systems. © 2021 American Chemical Society.