Electronic Structure And Magnetism Of Doped SrFeO₂: A First-principle Study

The iron-based perovskites(Sr, Ca) Fe O3-y have attracted great interest because of the peculiar physics and the potential to design the novel devices for the industrial applications. As a quasi-two-dimensional system, Sr Fe O2 adopts an unusual square-planar oxygen coordination around Fe2+. It is a G-type antiferromagnetic insulator and shows a remarkably high TN(473K) with strong structure stability against the heat, pressure and chemical substitution. We explore the charge carrier doping effect on the electronic and magnetic structures of Sr Fe O2 using the first-principle method. We demonstrate that the magnetic ground state will preserve G-type antiferromagnetic ordering in the electron doped systems. However, it changes to be A-type antiferromagnetic ground state at the critical hole-doping concentration, owing to the partically occupied Fe 2-2 and hybridized O 2p orbitals, favoring the intra-plane ferromagnetic coupling. Finally, we dope A site La and K atoms, respectively, and find the calculated results are in agreement with the simulated calculation.