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Among their numerous technological applications, semi-coherent oxide heterostructures have emerged as promising candidates for applications in intermediate temperature solid oxide fuel cell electrolytes, wherein interfaces influence ionic transport.Since misfit dislocations impact ionic transport in these materials, oxygen vacancy formation and migration at misfit dislocations in oxide heterostructures are central to their performance as an ionic conductor. Herein, we report high-throughput atomistic simulations to predict thousands of activation energy barriers for oxygen vacancy migration at misfit dislocations in SrTiO3/BaZrO3 heterostructures. Dopants display a noticeable effect as higher activation energies are uncovered in their vicinity. Interface layer chemistry has a fundamental influence on the magnitude of activation energy barriers since they are dissimilar at misfit dislocations as compared to coherent terraces. Lower activation energies are uncovered when oxygen vacancies migrate toward misfit dislocations, but higher energies when they hop away, revealing that oxygen vacancies would get trapped at misfit dislocations and impact ionic transport. The results herein offer atomic scale insights into ionic transport at misfit dislocations and fundamental factors governing the ionic conductivity of thin film oxide electrolytes.
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Mechanisms for oxygen vacancy defect migration in SrTiO3/NiO heterostructures: Effect of interface layer chemistry and misfit dislocation structure
Perovskite-based oxide heterostructures display promising properties resulting from interface phenomena, making them good candidates for next-generation solid oxide fuel cell electrolytes. Among the different features exhibited by these interfaces, misfit dislocations play an important role in influencing ionic transport, yet their role remains poorly understood, a phenomenon also observed in rock salt–perovskite interfaces. In SrTiO3/NiO heterostructures, we investigate oxygen vacancy migration near misfit dislocations using atomistic simulations in conjunction with a high-throughput nudged elastic band-based framework. By comprehensively mapping activation energy barriers across different interfacial chemistries and asymmetric structural features, we explore how the dislocation structure, which is dependent on the local interfacial chemistry, modulates oxygen vacancy migration. This study aims to shed light on the role of dopants, oxygen vacancies, interfacial chemistry, and extended defects in shaping ionic migration at the atomic scale. Misfit dislocations are often considered thermodynamic sinks for oxygen vacancies, oftentimes hindering ionic conductivity at such interfaces. We report dynamic behavior at interfaces that is largely dependent on the local coordination environment, challenging this conventional perspective. The study attempts to bridge the crucial gap in understanding interface-governed ion transport mechanisms in complex oxide heterostructures.
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- Award ID(s):
- 2042311
- PAR ID:
- 10660613
- Publisher / Repository:
- AIP Publishing
- Date Published:
- Journal Name:
- Journal of Applied Physics
- Volume:
- 138
- Issue:
- 9
- ISSN:
- 0021-8979
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript
- Journal Article:
- https://doi.org/10.1063/5.0283278
