Density functional study on redox energetics of LaMO3−δ (M=Sc–Cu) perovskite-type oxides

This study evaluates the redox energetics of LaMO3−δ (M=Sc–Cu) perovskite-type oxides via generalized gradient approximation (GGA) to DFT. Two different approaches to redox energetics of oxygen deficient perovskites of strongly non-stoichiometric (δ=0.5) and dilute defect limits (δ→0) are studied. In the first approach the enthalpies of oxidation are calculated using the stoichiometric end-compounds of LaMO3 and LaMO2.5. The most common structures for the reduced lanthanides and strontides similar to the ones experimentally reported for SrMnO2.5, SrFeO2.5, and LaNiO2.5 are considered. The second approach to the oxidation enthalpies termed (δ→0) follow the trend observed experimentally. This approach represents the experimental conditions of the measured oxygen enthalpies, and is hampered less by the artificial features due to spurious self-interaction errors in GGA.

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