Technical University of Denmark, Department of Energy Conversion and Storage, 2800 Kgs., Lyngby, Denmark.
Nanoscale. 2023 Feb 23;15(8):3704-3712. doi: 10.1039/d2nr07172j.
The heterostructure formed by depositing nanoscale thin films of spinel γ-AlO on perovskite SrTiO exhibits a range of exciting properties including room temperature epitaxial growth, high electron mobility, strain-tunable magnetic order, and a symmetry-related reordering of the conduction bands. In comparison to the benchmark LaAlO/SrTiO heterostructure, the γ-AlO/SrTiO heterostructure has been more sparsely investigated, which leaves plenty of room for scientific and technological discoveries. In this perspective article, I describe the key findings of the γ-AlO/SrTiO heterostructure and propose five directions for future research: (1) an exploration of novel phenomena emerging when relaxing the conventional epitaxial constraint of matching crystal structures across the interface, (2) a dynamic switching of a strong polarization through nanoscale electromigration of aluminum vacancies, (3) autonomous and forced enhancement of the electron mobility oxygen vacancy diffusion, (4) writing and erasing of magnetic and conducting nanolines using ferroelastic domain walls, and (5) a multiferroic state formed by combining ferroelectricity, ferromagnetism, and ferroelasticity. The proposed research directions may shed light on both fundamental aspects of the heterostructure and pave the way for applications within green energy devices and nanoelectronics.
在钙钛矿 SrTiO 上沉积尖晶石 γ-AlO 的纳米薄膜形成的异质结构表现出一系列令人兴奋的特性，包括在室温下外延生长、高电子迁移率、应变可调磁有序以及与对称性相关的导带重排。与基准 LaAlO/SrTiO 异质结构相比，γ-AlO/SrTiO 异质结构的研究较少，这为科学和技术发现留下了充足的空间。在这篇观点文章中，我描述了 γ-AlO/SrTiO 异质结构的关键发现，并提出了未来研究的五个方向：（1）探索在界面上放宽匹配晶体结构的传统外延约束时出现的新现象；（2）通过铝空位的纳米尺度电迁移实现强极化的动态切换；（3）通过氧空位扩散的自主和强制增强电子迁移率；（4）使用铁弹性畴壁写入和擦除磁和导电纳米线；（5）通过结合铁电性、铁磁性和铁弹性形成多铁态。所提出的研究方向可能揭示异质结构的基本方面，并为绿色能源设备和纳米电子学中的应用铺平道路。
