Fabrication of artifical heterostructures with possible oxygen ion conductions

我们探讨了人工异质结构的结构和输运性质，包括棕粒矿。这将为创造新型氧离子导体的进一步发展提供宝贵的基础见解。在本项目中，我们首先发现了缺氧铁基氧化物外延薄膜中的高温金属-绝缘体转变。这与块体的行为不同，铁基氧化物的金属-绝缘体转变温度最高，为620K。我们还建立了一种方法来澄清畸变在原子水平上使用环形光场成像在像差校正扫描透射电子显微镜（STEM）。通过这种方法，我们发现在张力薄膜中氧原子的位置有一定程度的自由。我们进一步制备了由褐铁矿和钙钛矿组成的异质结构，并发现了由于界面上没有氧空位有序而产生的新的导电行为。

We explore structural and transport properties of artificial heterostructures including brownmillerite. This would provide invaluable fundamental insight for further development in creating novel oxygen ion conductors. In this project, First we discover high-temperature metal-insulator transition in oxygen-deficient Fe-based oxide epitaxial thin films. This is distinct from the behavior for the bulk and the metal-insulator transition temperature of 620K is highest for the Fe-based oxide.We also established that an approach to clarify distortions at an atomic level using annular bright-field imaging in aberration-corrected scanning transmission electron microscopy (STEM). With this approach, we revealed that in a strained film there are some degrees of freedom of the oxygen atomic positions.We further fabricate heterostructure consisting of brownmillerite and perovskite and found the novel conducting behavior due to the absence of the oxygen vacancy ordering at the interface.