The correlation between the structural phase transition (SPT) and oxygen vacancy in SrRuO3 (SRO) thin films was investigated by in situ X-ray diffraction (XRD) and ambient pressure X-ray photoelectron spectroscopy (AP-XPS). In situ XRD shows that the SPT occurs from a monoclinic SRO phase to a tetragonal SRO phase near ∼200 °C, regardless of the pressure environment. On the other hand, significant core level shifts in both the Ru and Sr photoemission spectra are found under ultrahigh vacuum, but not under the oxygen pressure environment. The directions and behavior of the core level shift of Ru and Sr are attributed to the formation of oxygen vacancy across the SPT temperature of SRO. The analysis of in situ XRD and AP-XPS results provides an evidence for the formation of metastable surface oxide possibly due to the migration of internal oxygen atoms across the SPT temperature, indicating the close relationship between oxygen vacancy and SPT in SRO thin films.

中文翻译：

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薄膜SrRuO3 / SrTiO3（001）的结构相变与表面化学性质之间的相关性。

通过原位X射线衍射（XRD）和环境压力X射线光电子能谱（AP-XPS）研究了SrRuO3（SRO）薄膜中结构相变（SPT）与氧空位之间的相关性。原位X射线衍射表明SPT从约200°C的单斜SRO相变为四方SRO相，与压力环境无关。另一方面，在超高真空下，在Ru和Sr光发射光谱中都发现明显的核心能级移动，但在氧气压力环境下却没有。Ru和Sr的核心能级移动的方向和行为归因于SRO的SPT温度上氧空位的形成。