The exploration of physical properties of barium based Ba2TaXO6 (X=Sc, Y, La) double perovskite oxides for optoelectronic applications. A DFT study

Abstract

Currently, double perovskite oxides (DPO) with remarkable characteristics are the most suitable choices for optoelectronics devices. We report, for the first time, a comprehensive investigation of the structural, electronic, optical, magnetic, mechanical, vibrational, and thermodynamic properties of the double cubic perovskite oxides Ba₂TaXO₆ (X = Sc, Y, La), employing density functional theory (DFT) with the Perdew-Burke-Ernzerhof–generalized gradient approximation (PBE-GGA) within the CASTEP framework. The calculated lattice constants for Ba₂TaXO₆ (X = Sc, Y, La) are $a_o$ = 8.4281 Å, with lattice angles α = β = γ = 90°, confirming the cubic symmetry of these double perovskite oxides. The relatively high cohesive energy (−8.20 eV atom⁻¹) and formation energy (−6.18 eV atom⁻¹) of Ba₂TaLaO₆ indicate its enhanced structural stability. The calculated direct bandgaps of Ba₂TaScO₆ (3.11 eV), Ba₂TaYO₆ (3.17 eV) and Ba₂TaLaO₆ (3.22 eV) confirm their semiconducting nature. The valence band maximum derives primarily from the Ba–5p and O–2p orbitals, while the conduction band is dominated by the Sc–3d, Y–4d and La–5d states, thus enhancing the electronic conductivity. The minimum reflectance supports our belief that these perovskites can be highly beneficial for future optoelectronic applications. Ba₂TaXO₆ (X = Sc, Y, La) materials exhibit nonmagnetic behavior arising from spin-polarized density of states. Mechanical properties results endorse that the studied compounds are mechanically stable. Phonon dispersion analysis reveals dynamical stabilities in Ba₂TaYO₆. Our outcomes may open new avenues for researchers pursing advanced applications in optoelectronics