PL-1Precise Structural Observation and State Analysis

Abstract

Functional properties found in perovskite oxides are related to the octahedral distortion as well as the constituent elements. Heteroepitaxial thin films grown on different oxide are a good platform to control their functionalities. In order to elucidate the correlation between structural distortions induced by the lattice mismatch and properties of thin films, it is required to reveal the local structure in the vicinity of the interface precisely. High-angle annular dark-field (HAADF) and annular bright-field (ABF) imaging in aberration-corrected scanning transmission electron microscopy allows us for visualizing not only constituent cations but also oxygen atoms. It has been demonstrated that measuring atomic positions precisely from HAADF and ABF images is a good tool for analysis of structural distortions at oxide heterointerfaces [1]. Through such structural analysis we have recognized that the interfacial octahedral connection is an important factor controlling the properties of thin films. We have found that the octahedral connection can be engineered by A-site cation size [2] and the thickness of buffer layer inserted between the thin film and substrate [3].