First-principles electronic-structure calculation on the spin distribution and the half-metallic properties of the mixed valence iron compound Ba2F2Fe1.5S3

The first principles within the full potential linearized augmented plane wave (FP-LAPW) method with the generalized gradient approximation (GGA) approach were applied to study the new mixed valence compound Ba₂F₂Fe_1.5S₃. The density of states, the electronic band structure and the spin magnetic moment are calculated. The calculations reveal that the compound has an antiferromagnetic interaction between the Fe^III and Fe^II ions arising from the bridging S atoms, which validate the experimental assumptions that there is a low-dimensional antiferromagnetic interaction in Ba₂F₂Fe_1.5S₃. The spin magnetic moment mainly comes from the Fe^III and Fe^II ions with smaller contribution from S anion. By analysis of the band structure, we find that the compound has half-metallic property.