First-principles predictions of structure, half-metallic antiferromagnetism, optoelectronic, and elastic properties of double perovskites A2TaNiO6 (A = Ca, Sr, and Ba) for energy harvesting

Abstract

In this article, the electronic, half-metallic antiferromagnetism, and optical characteristics of A2TaNiO6 (A = Ca, Sr, and Ba) double perovskites have been investigated by using WIEN2k code with the GGA + PBEsol approximation. The cubic phase structures were optimized with minimum ground state energy. The electronic attributes showed a semiconductor nature for spin-up channels and a metallic nature for spin-down channels, indicating half-metallicity. Magnetic properties have demonstrated the magnetic moments and antiferromagnetic nature of the studied perovskites. The optical response was assessed by examining dielectric function, absorption coefficient, reflectivity, and energy loss function. Higher values of these parameters in the energy range of 2–4 eV suggest their potential for optoelectronics. Mechanical properties have been also investigated which demonstrated that these compounds have outstanding mechanical stability, anisotropy, mechanical strength, and ductility. The collective results reveal the importance of the analyzed compounds as promising candidates for spintronics, photovoltaics in space, UV-photodetectors, and other UV-based optoelectronic applications.