Yamamoto Takafumi, Chikamatsu Akira, Kitagawa Shunsaku, Izumo Nana, Yamashita Shunsuke, Takatsu Hiroshi, Ochi Masayuki, Maruyama Takahiro, Namba Morito, Sun Wenhao, Nakashima Takahide, Takeiri Fumitaka, Fujii Kotaro, Yashima Masatomo, Sugisawa Yuki, Sano Masahito, Hirose Yasushi, Sekiba Daiichiro, Brown Craig M, Honda Takashi, Ikeda Kazutaka, Otomo Toshiya, Kuroki Kazuhiko, Ishida Kenji, Mori Takao, Kimoto Koji, Hasegawa Tetsuya, Kageyama Hiroshi
Department of Energy and Hydrocarbon Chemistry, Graduate school of Engineering, Graduate School of Engineering, Nishikyo-ku, Kyoto, 615-8510, Japan.
Laboratory for Materials and Structures, Tokyo Institute of Technology, Yokohama, 226-8503, Japan.
Nat Commun. 2020 Nov 23;11(1):5923. doi: 10.1038/s41467-020-19217-7.
Perovskite oxides can host various anion-vacancy orders, which greatly change their properties, but the order pattern is still difficult to manipulate. Separately, lattice strain between thin film oxides and a substrate induces improved functions and novel states of matter, while little attention has been paid to changes in chemical composition. Here we combine these two aspects to achieve strain-induced creation and switching of anion-vacancy patterns in perovskite films. Epitaxial SrVO films are topochemically converted to anion-deficient oxynitrides by ammonia treatment, where the direction or periodicity of defect planes is altered depending on the substrate employed, unlike the known change in crystal orientation. First-principles calculations verified its biaxial strain effect. Like oxide heterostructures, the oxynitride has a superlattice of insulating and metallic blocks. Given the abundance of perovskite families, this study provides new opportunities to design superlattices by chemically modifying simple perovskite oxides with tunable anion-vacancy patterns through epitaxial lattice strain.
钙钛矿氧化物可以容纳各种阴离子空位有序结构，这会极大地改变它们的性质，但有序模式仍然难以操控。另外，薄膜氧化物与衬底之间的晶格应变会诱导功能改善和新的物质状态，而化学成分的变化却很少受到关注。在这里，我们将这两个方面结合起来，以实现应变诱导的钙钛矿薄膜中阴离子空位模式的产生和切换。外延SrVO薄膜通过氨处理被拓扑化学转化为缺阴离子的氮氧化物，与已知的晶体取向变化不同，缺陷平面的方向或周期性会根据所使用的衬底而改变。第一性原理计算验证了其双轴应变效应。与氧化物异质结构一样，氮氧化物具有绝缘和金属块的超晶格。鉴于钙钛矿家族的丰富性，这项研究提供了新的机会，通过外延晶格应变用可调谐的阴离子空位模式对简单的钙钛矿氧化物进行化学修饰来设计超晶格。
