Exploring Silicon-Based Ca₂TiSiO₆ Ordered Double Perovskite Oxides: a Comprehensive DFT Investigation of Structural, Dynamical, Mechanical Stability, and Optoelectronic Properties

In this research, the structural properties, phonons, mechanical stability, and optoelectronic properties of silicon-based Ca₂TiSiO₆ ordered double perovskites oxides are computed employing the DFT approach within the WIEN2K quantum mechanical code. The LDA, PBE-GGA, and TB-mBJ potentials are used, and it is found that the TB-mBJ potential gives more accurate results for optoelectronic properties. Our computed results for structural properties are entirely consistent with the experimental results. The calculations of phonons and the criterion of Born-Huang’s mechanical stability confirm the dynamical, structural, and mechanical stability of quaternary Si-based Ca₂TiSiO₆ material. The elastic constants C_ij, Pugh ratio B/G, and Poisson's ratio ʋ verify that the interested material is stiff, malleable, and resistant to shear strain. The computed spectral curves for various optical parameters reveal the robust responsiveness of the Ca₂TiSiO₆ material to UV wavelengths. This suggests promising applications in ultraviolet detectors, photo-catalysis, photo-detectors, solar cells, and other optoelectronic devices where efficient light absorption is essential for optimal functionality. Our research on silicon-based Ca₂TiSiO₆ double perovskite oxide will provide a base framework for experimental materials scientists.