Structural, electronic, and elastic properties of tetragonal BaTiO3 under pressure: DFT study

This study employs density functional theory to explore the structural, electronic, and elastic properties of tetragonal BaTiO 3 (BTO) under pressure. The calculated c/a and energy gap of 1.028 and 2.71 eV at 0 GPa, respectively, deviating by less than 5 % and 15.3 % from experimental values, validate the calculations. The research investigates the pressure-induced P 4 mm to P 4/ mmm phase transition at approximately 4.8 GPa, analyzing the electronic band structure with the mBJ technique and elastic property variations. Results indicate an indirect band gap (Γ to M) under tensile stress, decreasing with pressure in P 4/ mmm , while compressive stress shifts BTO to a direct band gap at Γ. Electron density differences highlight changes in charge distribution and bonding at the transition. Elastic moduli reveal a brittle-to-ductile shift near the phase transition, enhancing insights into pressure effects on BTO for technological optimization. • DFT study reveals pressure-induced P 4 mm to P 4/ mmm phase transition in BaTiO 3 at ∼4.8 GPa. • Indirect band gap (Γ-M) shifts to direct (Γ) with increasing pressure in P 4/ mmm phase. • Elastic moduli exhibit significant changes at phase transition, with brittleness-to-ductility shift. • Electron density difference shows symmetric charge distribution in P 4/ mmm under compression. • Results enhance understanding of BaTiO 3 for high-pressure technological applications.