Chemical expansion affected oxygen vacancy stability in different oxide structures from first principles calculations

• Chemical expansion of oxygen vacancies from first principles calculations.
• Oxygen vacancy stability manipulated via interfacial strain in layered materials.
• Neutral vacancies could stabilize in tensile-strained materials.
• Charged vacancies could stabilize in compressively-strained materials.

We study the chemical expansion for neutral and charged oxygen vacancies in fluorite, rocksalt, perovskite and pyrochlores materials using first principles calculations. We show that the neutral oxygen vacancy leads to lattice expansion whereas the charged vacancy leads to lattice contraction. In addition, we show that there is a window of strain within which an oxygen vacancy is stable; beyond that range, the vacancy can become unstable. Using CeO2|ZrO2 interface structure as an example, we show that the concentration of oxygen vacancies can be manipulated via strain, and the vacancies can be preferentially stabilized. These results could serve as guiding principles in predicting oxygen vacancy stability in strained systems and in the design of vacancy stabilized materials.

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