The interfaces in oxide heterostructures that bring novel physical phenomena and functionalities have attracted great attention in fundamental research and device applications. For uncovering structure–property relationships of oxide heterostructures, direct evidence of the atomic-scale structure of heterointerfaces is highly desired. Here, we report on studying the structure of interfaces between YBa2Cu3O7-δ thin films and SrTiO3 substrates by means of aberration-corrected ultrahigh-resolution electron microscopy. Employing advanced imaging and spectroscopic techniques, shifts of atoms at the interface away from the regular lattice sites are measured, leading to the interfacial polarity. The local polarization induced by the atomic shifts directs toward the cuprate films and is estimated to be about 36.1 μC/cm2. The observed interfacial polar layer is understood by the special atomic configuration across the interface, which could modulate the electrical properties in superconducting devices that are based on the ferroelectric/superconductor heterosystems.

中文翻译：

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铜酸盐-钛酸盐异质结构中界面极化的原子级成像

氧化物异质结构中的界面带来了新的物理现象和功能，在基础研究和器件应用中引起了极大的关注。为了揭示氧化物异质结构的结构-性质关系，非常需要异质界面原子级结构的直接证据。在这里，我们报告了通过像差校正的超高分辨率电子显微镜研究 YBa2Cu3O7-δ 薄膜和 SrTiO3 基板之间的界面结构。采用先进的成像和光谱技术，测量界面处原子远离规则晶格位点的位移，从而产生界面极性。由原子位移引起的局部极化指向铜酸盐薄膜，估计约为 36.1 μC/cm2。