Electronic structure of half-metal antiferromagnetism in double-perovskite BiPbVRuO₆and BiPbVOsO₆

We theoretically investigated the electronic structures of double-perovskite BiPbBB′O₆ by first-principles density functional calculation with generalized gradient approximation (GGA). These structures were fully optimized to yield half-metallic (HM) antiferromagnetic (AFM) materials. Among previously proposed HM-AFM materials, BB′ = VRu, VOs, MoRe, MoTc, WTc, and WRe were selected. Of the six BiPbBB′O₆ candidates, BiPbVRuO₆ and BiPbVOsO₆ with [001] (P4mm) and [111] (P4/nmm) stacked structures exhibited HM-AFM properties. The HM-AFM properties remained after GGA+U calculations, which were conducted to include on-site Coulomb interaction. We also explained that both the HM and AFM properties in the [001] and [111] structures mainly arise from the double exchange between neighboring transition-metal atoms via the mediating intra O atom.