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Different routes to charge disproportionation in perovskites-type Fe oxides

J. Matsuno·T. Mizokawa·A. Fujimori·Y. Takeda·S. Kawasaki·M. Takano
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Abstract

Iron perovskites CaFeO_3 and La_{0.33}Sr_{0.67}FeO_3 show charge disproportionation, resulting in charge-ordered states with Fe^{3+}:Fe^{5+} =1:1 and =2:1, respectively. We have made photoemission and unrestricted Hartree-Fock band-structure calculation of CaFeO_3 and compared it with La_{0.33}Sr_{0.67}FeO_3. With decreasing temperature, a gradual decrease of the spectral weight near the Fermi level occurred in CaFeO_3 as in La_{0.33}Sr_{0.67}FeO_3 although lattice distortion occurs only in CaFeO_3. Hartree-Fock calculations have indicated that both the breathing and tilting distortions are necessary to induce the charge disproportionation in CaFeO_3, while no lattice distortion is necessary for the charge disproportionation in La_{0.33}Sr_{0.67}FeO_3.

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J. Matsuno, T. Mizokawa, A. Fujimori, Y. Takeda, S. Kawasaki, M. Takano. 2002-07-10. Different routes to charge disproportionation in perovskites-type Fe oxides. https://doi.org/10.1103/physrevb.66.193103

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