A deep dive into structural, electronic, optical, and mechanical properties of ATiO₃ (A = Ba, Th): DFT insights

Different physical characteristics (structural, optical, electronic, and mechanical) of ThTiO3 were explored using DFT and compared to BaTiO3. ThTiO3 has been determined to be mechanically and thermodynamically stable based on the simulation results, which were validated using the Born stability criteria and formation energy. Furthermore, a significant modification in the traits of ThTiO3 has been revealed compared to BaTiO3. For example, after the complete substitution of Ba by Th, in the case of GGA-PBE, the band gap increases from 1.82 eV to 3.37 eV, while in the case of HSE-06, it increases from 3.254 eV to 4.21 eV, also converting from indirect to direct bandgap. Not only that, but ThTiO3 has become an n-type degenerate semiconductor from a conventional semiconductor, which assures potential applications in tunnel diodes, high-frequency transistors, photocatalysts, etc. ThTiO3 is an appropriate material for capacitors, optoelectronic, and high k nanoelectronics devices based on the high dielectric constant value, which is higher than BaTiO3. Moreover, with Th substitution, BaTiO3 transitioned from brittle to ductile, which ensures its suitability for industrial machining processes. Furthermore, this substitution also improved the material's anisotropic behavior, as the Zener Anisotropy value for ThTiO3 is also higher than BaTiO3. We believe this investigation will open another door in the field of materials for microelectronics and optoelectronics enthusiasts.