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.

中文翻译：

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具有可定制晶面的二维稀土氧化物单晶的一般合成

二维 (2D) 稀土氧化物 (REO) 是一大类材料，具有各种有趣的应用，精确的晶面控制对于研究二维极限中的新特性至关重要。然而，由于固有的非层状结构和不同晶面的不同热力学稳定性，在获得具有特定晶面的二维单晶方面仍然存在瓶颈。在此，我们首次通过设计用于控制预定晶面的二维成核和调节生长的硬-软-酸-碱对，实现了具有可定制晶面的各种高质量二维 REO 单晶的合成。晶体的模式和方向。此外，还揭示了二维 REO 单晶的晶面相关磁性。