Understanding the Unique Structural and Electronic Properties of SrFeO2
Abstract
We report a first-principles study of SrFeO2, an infinite-layer oxide with Fe atoms in a perfect square-planar coordination down to essentially 0 K. Our results reveal this striking behavior relies on the double occupation of the 3dz2 orbitals of high-spin Fe2+. Such an electronic state results from the hybridization of iron's 3dz2 and 4s orbitals, which enables a large reduction of the intra-atomic exchange splitting of the z2 electrons. The generality of the phenomenon is discussed.
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