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

Abstract

Perovskite oxides hold promise for energy and quantum technologies, but wide-gap hosts like NaAlO3 are limited by poor transport and deep-UV absorption. Using first-principles GGA + U + SOC calculations, we investigate Eu3+-, Gd3+-, and Tb3+-doped NaAlO3, 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 (similar to 6.2 eV) to similar 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 (similar to 2.0-2.2 eV), large dielectric constants (epsilon(1)(0) approximate to 95 for Eu), and plasmonic resonances near 4 eV, enabling visible-light harvesting. Elastic analysis indicates slight lattice softening with preserved ductility (B/G approximate to 1.56-1.57). Thermoelectric results show Seebeck coefficients >210 mu V/K (Eu, Tb) with ZT similar to 0.45 at 500 K, surpassing pristine NaAlO3. These findings position rare-earth-doped NaAlO3 as a multifunctional platform for photovoltaics, photocatalysis, thermoelectrics, and spintronics.