General synthesis of 2D rare-earth oxide single crystals with tailorable facets
Linyang Li, Fangyun Lu, Wenqi Xiong, Yu Ding, Yangyi Lu, Yao Xiao, Xin Tong, Yao Wang, Shuangfeng Jia, Jianbo Wang, Rafael G. Mendes, Mark H. Rümmeli, Shengjun Yuan, Mengqi Zeng, Lei Fu
Abstract
Two-dimensional (2D) rare-earth oxides (REOs) are a large family of materials with various intriguing applications and precise facet control is essential for investigating new properties in the 2D limit. However, a bottleneck remains with regard to obtaining their 2D single crystals with specific facets because of the intrinsic non-layered structure and disparate thermodynamic stability of different facets. Herein, for the first time, we achieve the synthesis of a wide variety of high-quality 2D REO single crystals with tailorable facets via designing a hard-soft-acid-base couple for controlling the 2D nucleation of the predetermined facets and adjusting the growth mode and direction of crystals. Also, the facet-related magnetic properties of 2D REO single crystals were revealed. Our approach provides a foundation for further exploring other facet-dependent properties and various applications of 2D REO, as well as inspiration for the precise growth of other non-layered 2D materials.