Identification of vacancy defects in a thin film perovskite oxide
Identification of vacancy defects in a thin film perovskite oxide
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DOI：
10.1103/physrevb.81.064102
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发表时间：
2010-02-01
影响因子：
3.7
通讯作者：
Jackson, T. J.
中科院分区：
文献类型：
--
作者：
Keeble, D. J.;Mackie, R. A.;Jackson, T. J.
空位是钙钛矿氧化物中的主要点缺陷，然而，检测和识别薄膜中空位缺陷的性质仍然具有挑战性。这可以使用电子束方法来实现，但需要几个百分点的浓度。在这里，我们使用高通量正电子束，提供高统计正电子寿命测量，以识别 SrTiO3 上激光烧蚀的 SrTiO3 中的空位。该方法能够达到百万分之一的灵敏度，并且与密度泛函理论结合时可以提供局部结构信息。正电子寿命谱深度剖面可检测表面层中大空位簇的存在、整个薄膜中 Sr 空位的均匀分布，并解析与基底的界面。
Vacancies are the dominant point defects in perovskite oxides, however, detecting and identifying the nature of vacancy defects in thin films remains challenging. This can be achieved using electron-beam methods but concentrations of several percent are required. Here we use a high-flux positron beam, providing high statistics positron lifetime measurements, to identify vacancies in laser ablated SrTiO3 on SrTiO3. The method is capable of subparts per million sensitivity and when combined with density-functional theory provides local structure information. The positron lifetime spectrum depth profile detects the presence of large vacancy clusters in a surface layer, a uniform distribution of Sr vacancies through the bulk of the film and resolves the interface with the substrate.