FP-LAPW study of energy bands and optical properties of the filled skutterudite $$\hbox {CeRu}_{4}\hbox {As}_{12}$$ CeRu 4 As 12 with spin–orbit coupling

Abstract

The density functional theory (DFT)-based fully relativistic version of the full-potential linearized augmented plane wave method with spin---orbit coupling (SOC) has been used to study the electronic and optical properties of the filled skutterudite $$\hbox {CeRu}_{4}\hbox {As}_{12}$$CeRu4As12. The exchange and correlation potential has been treated with the local density approximation (LDA). The analysis of the density of states and energy bands in the vicinity of the Fermi energy level suggests the semiconducting nature of the material with narrow indirect energy band gap of 0.11 eV; however, the gap value increases to 0.17 eV for without SOC calculation. Additionally, the modified Becke---Johnson (mBJ) potential has been utilized along with the LDA approach to estimate the precise value of the energy band gap of the material. The mBJ treatment enhances the energy band gap to ź0.2 eV. In order to understand the structural and mechanical properties of the sample material, the elastic constants are also estimated at ambient conditions. The analysis of the elastic constants suggests the brittle nature of the material whose stiffness is comparable with that of $$\hbox {CeOs}_{4}\hbox {Sb}_{12}$$CeOs4Sb12 and the covalent contribution is expected in the bonding. The optical response of the material has been studied from the energy bands, which reflects the metallic behavior of the material in the infrared region of frequency radiation and turns to act as opaque material with superluminal behavior at ultraviolet frequency radiation. The inclusion of the hybrid functional in the calculation suggests the metallic nature of the material.