2018/05/24 by Jinyoung Lim, Jaejun Yu · 39 citations
Materials Science · Physics and Astronomy · #Advanced Condensed Matter Physics #Algorithm #Computer science #Electronic and Structural Properties of Oxides #Magnetic and transport properties of perovskites and related materials #State (computer science) #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.98.085106
published in Physical review. B./Physical review. B 98(8) (American Physical Society) · 13 pages, 10 figures
arxiv created 2018/05/24 · openalex created_date 2018/06/01 · openalex publication_date 2018/08/06 · arxiv updated 2018/08/15 · openalex updated_date 2026/08/05
We present the first-principles investigation of the structural, electronic, and magnetic properties of SrCoO_3\ensuremath-\ensuremathδ (\ensuremathδ=0,0.25,0.5) to understand the multivalent nature of Co ions in SrCoO_3\ensuremath-\ensuremathδ along the line of topotactic transition between perovskite SrCoO3 and brownmillerite SrCoO2.5. From the onsite Coulomb interaction U-dependent ground state of stoichiometric SrCoO3, we show the proximity of its metallic ferromagnetic ground state to other antiferromagnetic states. The structural and magnetic properties of SrCoO_3\ensuremath-\ensuremathδ depending on their oxygen content provide an interesting insight into the relationship between the Co-Co distances and the magnetic couplings so that the spin-state transition of Co spins can be understood by the change of pd hybridization depending on the Co-Co distances. The strong suppression of the dp\ensuremathσ hybridization between Co d and O p orbitals in brownmillerite SrCoO2.5 brings on the high-spin state of Co3+\phantom\rule4pt0exd6 and is responsible for the antiferromagnetically ordered insulating ground state. The increase of effective Co-Co distances driven by the presence of oxygen vacancies in SrCoO_3\ensuremath-\ensuremathδ is consistent with the reduction of the effective pd hybridization between Co d and O p orbitals. We conclude that the configuration of neighboring Co spins is shown to be crucial to their local electronic structure near the metal-to-insulator transition along the line of the topotactic transition in SrCoO_3\ensuremath-\ensuremathδ. Incidentally, we also find that the I2mb symmetry of SrCoO2.5 is energetically stable and exhibits ferroelectricity via the ordering of CoO4 tetrahedra, where this polar lattice can be stabilized by the presence of a large activation barrier.