title: Low-Dimensional Oxygen Vacancy Ordering and Diffusion in SrCrO3-δ.
abstract: We investigate the formation mechanisms of vacancy-ordered phase and collective mass transport in epitaxial SrCrO3-δfilms using ab initio simulations within the density functional theory formalism. We show that as the concentration of oxygen vacancies (VO) increases, they form 1D chains that feature Cr-centered tetrahedra. Aggregation of these 1D VOchains results in the formation of (111)-oriented oxygen-deficient planes and an extended vacancy-ordered phase observed in recent experiments. We discuss atomic-scale mechanisms enabling the quasi-2D VOaggregates to expand along and translate across (111) planes. The corresponding lowest activation energy pathways necessarily involve rotation of Cr-centered tetrahedra, which emerges as a universal feature of fast ionic conduction in complex oxides. These findings explain reversible oxidation and reduction in SrCrO3-δat low temperatures and provide insights into transient behavior necessary to harness ionic conductive oxides for high-performance and low-temperature electrochemical reactors.
authors.affiliation: Physical Sciences Division, Physical & Computational Sciences Directorate, Pacific Northwest National Laboratory , Richland, Washington 99352, United States.
authors.forename: Phuong-Vu
authors.identifier: http://orcid.org/0000-0001-8613-1690
authors.initials: PV
authors.lastname: Ong
authors.affiliation: Physical Sciences Division, Physical & Computational Sciences Directorate, Pacific Northwest National Laboratory , Richland, Washington 99352, United States.
authors.forename: Yingge
authors.initials: Y
authors.lastname: Du
authors.affiliation: Physical Sciences Division, Physical & Computational Sciences Directorate, Pacific Northwest National Laboratory , Richland, Washington 99352, United States.
authors.forename: Peter V
authors.initials: PV
authors.lastname: Sushko