DFT+U screening of the physical properties of XWO3 (X=Sr, Cd) perovskite oxides

Abstract

We report a DFT + U study of the structural, electronic, mechanical, optical, phonon dispersion, and thermodynamic properties of newly developed XWO₃ (X = Sr, Cd) perovskites. The Goldschmidt tolerance factor, octahedral factor, elastic constants, and phonon dispersions reveals that both materials maintain structural, mechanical, and dynamic stability. Both materials display metallic behavior in their electronic band structures. DOS reveals that the W d and O-p states underlie the metallic character. Mechanical properties demonstrate elastic anisotropy and display ductile behavior. Optical properties are also addressed in this study by compiling energy electron loss function, refractive index, extinction coefficient, absorption coefficient, and complex dielectric tensor. Debye temperature (θ_D), Grüneisen parameter (γ), specific heat at constant volume (C_V), and entropy (S) have been also computed as a function of temperature (0−1000 K) and pressure (0−8 GPa) using the quasi-harmonic Debye model. Finally, XWO₃ possess low lattice thermal conductivity (κ_L < 2.0 W m⁻¹. K⁻¹), which is recommended for thermoelectric systems.