Structural, Mechanical, Electronic, Optical, and Thermodynamic Properties of New Oxychalcogenide A2O2B2Se3 (A = Sr, Ba; B = Bi, Sb) Compounds: A First-Principles Study

The structural, mechanical, electronic, and optical characteristics of Alkali chalcogenide oxychalcogenides, i.e., A2O2B2Se3 (A = Sr, Ba; B Bi, Sb), were investigated using density functional theory (DFT). After full relaxation, the obtained structural parameters are in good agreement with experimental parameters. Furthermore, calculated elastic stiffness Cij shows that all studied compounds followed mechanical stability criteria. Ductility for these was analyzed by calculating Pugh’s ratio; we classified Sr2O2Bi2Se3, Sr2O2Sb2Se3, Ba2O2Bi2Se3 as ductile, Ba2O2Sb2Se3 brittle. Debye temperature acoustic velocity estimated. In addition, electronic chemical bonding properties from analysis band structure state. main features valence conduction bands partial states. Electronic structures mainly contributed to Se-4p Bi-6p/Sb-5p Direct gaps 0.90, 0.47, 0.73 eV Ba2O2Sb2Se3, respectively. compound has an indirect gap 1.12 eV. interpreted quantified properties, including dielectric function, absorption coefficient, reflectivity, refractive index. From reflectivity spectra, can state will be useful applications.