Inclusive DFT studies on electronic, optical, mechanical, elastic, X-ray diffraction, thermodynamic, and spectroscopic analysis of cubic BaCeO3 under high hydrostatic stress

This study investigates the modulation of various characteristics of BaCeO₃ under hydrostatic stress using the ultrasoft pseudopotential method and the generalized gradient approximation approach. The structural, electronic, mechanical, optical, and thermodynamic properties were computed, alongside spectroscopic and structural characterization. The results revealed that, despite a 33% reduction in lattice volume and a 12% decrease in lattice parameters due to applied hydrostatic stress, the crystal lattice retained its cubic structure, with no phase transition observed. The electronic band gap varied from 2.641 eV to 2.711 eV under stresses of 0–50 GPa and decreased to 1.65 eV at 100 GPa. Hydrostatic stress influences not only the electronic structure but also optical properties such as reflectivity, refractive index, absorption, energy loss function, and dielectric function. The increased absorption peak intensity and the shift of these peaks to higher energies suggested a blueshift, indicating the material’s suitability for optoelectronic applications. Mechanical parameters, including bulk, shear, and Young’s moduli, confirmed the material’s stiffness, mechanical stability, and resistance to shear deformation. Under stress, the material was found to be less compressible, stiffer to shear stress, and less elastic. Thermodynamic analysis showed that, as stress increased, the total enthalpy, entropy, and heat capacity of the material decreased, while the average atomic vibrations and equilibrium state improved.