Oxygen vacancies (Vo) play significant roles in determining the properties of transition-metal oxides. However, the concentration of Vo cannot be tuned quantitatively by optimizing the preparation conditions, and the precise control of Vo distribution at the atomic scale is even more challenging. Here, by controlling the reversible phase transitions between perovskite LaCoO₃ (PV-LCO) and brownmillerite LaCoO_2.5, we realize the tuning of Vo in PV-LCO, including the concentration with quantitative precision and the spatial distribution at the atomic scale. With the first principles calculations, we clarify that two thirds of Vo in PV-LCO can be eliminated after a cycle of the reversible phase transitions, and all the residual Vo are confined in specific lattice sites in PV-LCO. Such an ordered distribution of Vo can help to enhance the ferromagnetism of PV-LCO.

中文翻译：

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LaCoO3薄膜中氧空位的原子尺度调节

氧空位（V o）在确定过渡金属氧化物的性质中起着重要作用。但是，不能通过优化制备条件来定量地调节V o的浓度，并且在原子尺度上精确控制V o的分布甚至更具挑战性。在这里，通过控制钙钛矿型LaCoO ₃（PV-LCO）和褐铁矿型LaCoO _2.5之间的可逆相变，我们实现了PV-LCO中V o的调节，包括定量精度的浓度和原子级的空间分布。通过第一原理的计算，我们澄清了V的三分之二循环可逆相变之后，可以消除PV-LCO中的o，并且将所有残余V o限制在PV-LCO中的特定晶格位置。V o的这种有序分布可以帮助增强PV-LCO的铁磁性。