DFT and DFT+U investigation of the effect of spin–orbit interaction and exchange-correlation energy on electronic and magnetic structures of Ir-based double perovskites Ba2TIrO6 (T = Cr, Mn, and Fe)

Abstract

This study utilizes the generalized gradient approximation (GGA) and GGA+U methods within the first-principles density functional theory to investigate the electronic and magnetic structures of Ir5+-based double perovskites Ba2TIrO6 (T = Cr, Mn, and Fe). Also, we include the spin–orbit (SO) interaction to incorporate the scalar relativistic effect in calculations. The structural optimizations and stability revealed that Ba2TIrO6 exhibits a cubic structure (space group Fm-3m). GGA+U and GGA+SO+U yield quite accurate results of the bandgaps and conduction states as compared to GGA and GGA+SO methods. The total and partial densities of states (DOSs) predict that Ba2TIrO6 shows two behaviors: half-metallic (T = Cr) and metallic (T = Mn and Fe), wholly transforming to the half-metallicity nature when SO and U are jointly turned on within the GGA+SO+U method. Moreover, the results of magnetic structures expose the existence of ferromagnetic (T = Cr and Fe) and antiferromagnetic (T = Mn) orderings in Ba2TIrO6 via 180°-superexchange T3+–O2−–Ir5+. Analysis of the DOSs and magnetic moments shows that the inclusion of the SO interaction has an insignificant effect on Ir-5d4 electrons in all compounds.