Controlling the surface structure on the atomic scale is a major difficulty for most transition metal oxides; this is especially true for the ternary perovskites. The influence of surface stoichiometry on the atomic structure of the SrTiO3(001) surface was examined with scanning tunneling microscopy, low-energy electron diffraction, low-energy He+ ion scattering (LEIS), and X-ray photoelectron spectroscopy (XPS). Vapor deposition of 0.8 monolayer (ML) strontium and 0.3 ML titanium, with subsequent annealing to 850 °C in 4 × 10− 6 mbar O2, reversibly switches the surface between c(4 × 2) and (2 × 2) reconstructions, respectively. The combination of LEIS and XPS shows a different stoichiometry that is confined to the top layer. Geometric models for these reconstructions need to take into account these different surface compositions.

中文翻译：

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化学计量驱动的 SrTiO3(001) 表面重建之间的切换

对于大多数过渡金属氧化物来说，在原子尺度上控制表面结构是一个主要困难；对于三元钙钛矿尤其如此。通过扫描隧道显微镜、低能电子衍射、低能He+离子散射(LEIS)和X射线光电子能谱(XPS)研究了表面化学计量对SrTiO3(001)表面原子结构的影响。0.8 单层 (ML) 锶和 0.3 ML 钛的气相沉积，随后在 4 × 10− 6 mbar O2 中退火至 850 °C，分别在 c(4 × 2) 和 (2 × 2) 重建之间可逆地切换表面。LEIS 和 XPS 的组合显示出仅限于顶层的不同化学计量。这些重建的几何模型需要考虑这些不同的表面成分。