Magnetic and optical anomalies in infinite-layer iron oxide CaFeO2 and BaFeO2: A density functional theory investigation

Based on density functional theory with the generalized gradient approximation plus on-site Coulomb repulsion method, we study the electronic, magnetic, and optical properties in infinite-layer iron oxide CaFeO2 and BaFeO2. It is revealed that CaFeO2 possesses a P4¯21m tetragonal symmetry. And the s...

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Veröffentlicht in:Journal of applied physics 2009-11, Vol.106 (9)
Hauptverfasser: Ju, Sheng, Cai, Tian-Yi
Format: Artikel
Sprache:eng
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Zusammenfassung:Based on density functional theory with the generalized gradient approximation plus on-site Coulomb repulsion method, we study the electronic, magnetic, and optical properties in infinite-layer iron oxide CaFeO2 and BaFeO2. It is revealed that CaFeO2 possesses a P4¯21m tetragonal symmetry. And the single down-spin electron of Fe2+ occupies dz2 level instead of Jahn–Teller instability from the double degenerated dx2−y2 and dz2 levels predicted in crystal field theory. Magnetic structure shows great contrast between intralayer and interlayer exchange interactions. Linear dielectric function, on the other hand, exhibits obvious anisotropic behavior between in plane and out of plane responses. For the larger ionic size of Ba, BaFeO2 is found to have a P4/mmm tetragonal symmetry, which is similar with SrFeO2. In the mean time, both magnetic and optical properties exhibit much stronger anisotropic behavior. Together with the previous calculations of SrFeO2, it is found the anisotropic behaviors in these two dimensional structures are robust and independent of A-site size.
ISSN:0021-8979
1089-7550
DOI:10.1063/1.3238271