Realization of half-metal antiferromagnetic (HM-AFM) behaviour in double perovskite Sr2CrReO6 on substitution of Tc at Cr site: Promising material for optoelectronics and thermoelectric applications via DFT framework

Using the first principles approach within the Full Potential Linearized Augmented Plane wave (FP-LAPW) method, the electronic, magnetic, optical and thermoelectric properties of double perovskite oxides Sr2AReO6 (A = Cr, Tc) were systematically investigated. We have used the most appropriate functionals like PBEsol-GGA and PBEsol + U. The replacement of Cr atom by Tc atom in Sr2CrReO6 leads to the transition of the magnetic configuration from ferrimagnet to complete antiferromagnet half-metal (AFM-HM) with zero magnetic moments. The mechanisms that govern the ferrimagnetism/antiferromagnetism in the two double perovskites are the Zener double exchange and p-d hybridization, respectively. A careful analysis of the optical and thermoelectric properties in this study leads to the conclusion that the antiferromagnet double perovskite Sr2TcReO6 (STRO) has the power to convert the maximum amount of sunlight in the visible range as compared to Sr2CrReO6(SCRO). Further, we have obtained an optimal figure of merit (ZT ∼ 1) and high electrical conductivity. Finally, the half-metallic antiferromagnetic double perovskite STRO is a potential energy material for the spintronic device, photovoltaic solar cells and thermoelectric applications.