Computational study reveals tunable band gaps and high optical absorption in BaThO3 and BaThX3 perovskites, indicating potential for optoelectronic and photovoltaic applications.
Key Points
To systematically evaluate the structural, electronic, optical, mechanical, and thermal properties of BaThO3 and its chalcogen-substituted derivatives BaThX3 (X = S, Se, Te).
Conducted first-principles calculations to model cubic BaThO3 and BaThX3 (X = S, Se, Te) perovskite structures.
Evaluated dynamical and mechanical stability using phonon dispersion calculations and elastic analyses.
Analyzed electronic band structures, Th-derived f-orbital contributions, and frequency-dependent optical response functions.
All compounds maintain stable cubic structures with lattice expansion and phonon softening across the series, showing mechanical ductility and dynamic stability in BaThO3, BaThS3, and BaThTe3.
Chalcogen substitution systematically decreases band gaps from BaThO3 to BaThTe3 while driving a transition from direct to indirect band gap nature.
Optical absorption increases to high coefficients (~10^6 cm^-1) across the series, shifting absorption from the ultraviolet in BaThO3 to visible light in BaThS3 and BaThSe3, and into the infrared in BaThTe3.