First-principles investigation of electronic, magnetic and optical properties of double perovskite oxides Ba2NiYO6 (Y = Pd, Pt)

Abstract

The different properties of Ba₂NiPdO₆ and Ba₂NiPtO₆ double perovskite alloys are analyzed using a density functional theory simulation performed with Wien2k. First, structural optimization computed by adopting the Generalized Gradient Approximation (GGA) showed that both alloys indeed have a cubic C 1b structure with a ferromagnetic phase. Other approximation methods, including the GGA plus Hubbard potential (GGA+U), the GGA+U+spin orbit coupling (GGA+U+SOC) and the modified Bece–Johnson potential (mBJ), have demonstrated that these compounds are half-metallic and have a band gap suitable for solar applications. The overall magnetic moment is 4µ_B per formula unit (fu), with Ni atoms contributing significantly. Furthermore, the low reflectivity and high optical absorption of double perovskites indicate their potential for various optoelectronic fields beyond photovoltaics.