A DFT study of the structural, electronic, optical, thermoelectric, and thermodynamic properties of the halide double perovskite Cs2CeCl6

Abstract

This study presents a comprehensive investigation of the structural, electronic, optical, thermodynamic, and thermoelectric properties of the halide double perovskite Cs₂CeCl₆ using density functional theory (DFT) with the LSDA + mBJ approach in the Wien2k package. Our work is the first to explore the electronic properties of Cs₂CeCl₆, identifying it as a p-type semiconductor with a band gap of approximately 1.828 eV. Optical analysis reveals strong absorption in the UV-visible range, with a detailed evaluation of the absorption coefficient, electron energy loss, refractive index, extinction coefficient, and the real and imaginary parts of the dielectric tensor and optical conductivity. The observed increase in Debye temperature under pressure suggests enhanced thermal conductivity, crucial for understanding its behavior under varying conditions. Thermoelectric analysis shows that the figure of merit (ZT) improves with higher Seebeck coefficients and electrical conductivity but decreases with increasing thermal conductivity, illustrating the delicate balance needed to optimize thermoelectric performance.