Rare-earth engineering of NaAlO3 perovskites unlocks unified optoelectronic, thermoelectric, and spintronic functionalities

Perovskite oxides hold promise for energy and quantum technologies, but wide-gap hosts like NaAlO 3 are limited by poor transport and deep-UV absorption. Using first-principles GGA+U+SOC calculations, we investigate Eu 3+ -, Gd 3+ -, and Tb 3+ -doped NaAlO 3 , analyzing electronic, optical, elastic, and thermoelectric properties. Rare-earth substitution is thermodynamically favorable (formation energies 1.2–1.6 eV) and induces strong f–p hybridization, reducing the pristine bandgap (∼6.2 eV) to ∼3.1 eV (Tb). Spin-resolved band structures reveal Gd-driven half-metallicity, Eu-induced spin-selective metallicity, and Tb-stabilized p-type semiconducting behavior. Optical spectra show red-shifted absorption (∼2.0–2.2 eV), large dielectric constants (ε 1 (0) ≈ 95 for Eu), and plasmonic resonances near 4 eV, enabling visible-light harvesting. Elastic analysis indicates slight lattice softening with preserved ductility (B/G ≈ 1.56–1.57). Thermoelectric results show Seebeck coefficients >210 μV/K (Eu, Tb) with ZT ∼0.45 at 500 K, surpassing pristine NaAlO 3 . These findings position rare-earth-doped NaAlO 3 as a multifunctional platform for photovoltaics, photocatalysis, thermoelectrics, and spintronics. • First-principles study of Eu 3+ -, Gd 3+ -, Tb 3+ -doped NaAlO 3 using GGA+U+SOC. • Thermodynamically favorable doping with formation energies 1.2–1.6 eV. • Bandgap narrows from 6.2 eV to 3.1 eV, with Gd inducing half-metallicity. • Red-shifted absorption (∼2.0–2.2 eV) and giant dielectric constant (ε 1 (0) ≈ 95). • Enhanced thermoelectricity (Seebeck >210 μV/K, ZT ∼0.45 at 500 K) with robust mechanics.