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dc.contributor.authorMarthinsen, Astrid
dc.contributor.authorGrande, Tor
dc.contributor.authorSelbach, Sverre Magnus
dc.identifier.citationJournal of Physical Chemistry C. 2020, 124 12922-12932.en_US
dc.description.abstractThe microscopic origin of chemical expansion in perovskite oxides, due to formation of oxygen vacancies accompanied by formal reduction of a 3d transition metal, is studied by first-principles calculations. We compare the II–IV manganite and titanate series, having Ca, Sr, or Ba on the A site. In particular, the effect of electron localization is elucidated by systematically varying the Hubbard U, and we find that the localization behavior is significantly different in the manganites and titanates. The chemical expansion is explicitly calculated for all compounds, and we demonstrate that increasing on-site repulsion (Hubbard U) on the B site in the lattice yields increased chemical expansion in the manganites and reduced chemical expansion in the titanates. The opposite behavior of the manganites and titanates arises from different electrostatic screenings of oxygen vacancies. We show that this can be attributed to differences in electronic energy levels, specifically that Mn–O bonds are more covalent than Ti–O bonds. Fundamental understanding of electronic and crystal chemical origins of the important phenomenon of chemical expansion is required for rational design of oxide materials for energy technology, sensors, and actuators. We hope our analysis will inspire further fundamental studies of other oxides for solid state ionics applications.en_US
dc.publisherAmerican Chemical Societyen_US
dc.rightsNavngivelse 4.0 Internasjonal*
dc.titleMicroscopic Link between Electron Localization and Chemical Expansion in AMnO3 and ATiO3 Perovskites (A = Ca, Sr, Ba)en_US
dc.typePeer revieweden_US
dc.typeJournal articleen_US
dc.source.journalJournal of Physical Chemistry Cen_US
dc.description.localcodeACS AuthorChoice with CC-BY license.en_US

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