Two-dimensional (2D) ferromagnets with high Curie temperature have long been the pursuit for electronic and spintronic applications. CrI3 is a rising star of intrinsic 2D ferromagnets, however, it suffers from weak exchange coupling. Here we propose a general strategy of self-intercalation to achieve enhanced ferromagnetism in bilayer CrI3. We showed that filling either Cr or I atoms into the van der Waals gap of stacked and twisted CrI3 bilayers can induce the double exchange effect and significantly strengthen the interlayer ferromagnetic coupling. According to our first-principles calculations, the intercalated native atoms act as covalent bridge between two CrI3 layers and lead to discrepant oxidation states for the Cr atoms. These theoretical results offer a facile route to achieve high-Curie-temperature 2D magnets for device implementation.

中文翻译：

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通过自插层增强 CrI3 双层的铁磁性

具有高居里温度的二维 (2D) 铁磁体长期以来一直是电子和自旋电子应用的追求。CrI3 是本征 2D 铁磁体的后起之秀，然而，它受到弱交换耦合的影响。在这里，我们提出了一种自嵌入的一般策略，以在双层 CrI3 中实现增强的铁磁性。我们表明，将 Cr 或 I 原子填充到堆叠和扭曲的 CrI3 双层的范德华间隙中可以引起双重交换效应并显着增强层间铁磁耦合。根据我们的第一性原理计算，嵌入的天然原子充当两个 CrI3 层之间的共价桥，导致 Cr 原子的氧化态不一致。这些理论结果为实现用于器件实现的高居里温度 2D 磁体提供了一条简便的途径。