Few-layer CrI 3 is the most known example among two-dimensional (2D) ferromagnets, which have attracted growing interest in recent years. Despite considerable efforts and progress in understanding the properties of 2D magnets both from theory and experiment, the mechanism behind the formation of in-plane magnetic ordering in chromium halides is still under debate. Here, we propose a microscopic orbitally-resolved description of ferromagnetism in monolayer CrI 3 . Starting from first-principles calculations, we construct a low-energy model for the isotropic Heisenberg exchange interactions. We find that there are two competing contributions to the long-range magnetic ordering in CrI 3 : (i) Antiferromagnetic Anderson’s superexchange between half-filled t 2 g orbitals of Cr atoms; and (ii) Ferromagnetic exchange governed by the Kugel–Khomskii mechanism, involving the transitions between half-filled t 2 g ...

中文翻译：

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单层CrI 3的轨道分辨铁磁性

二维（2D）铁磁体中很少有CrI 3层，这在近年来引起了越来越多的兴趣。尽管在理论和实验上都对理解2D磁体的性能做出了巨大的努力和进步，但是在卤化铬中形成面内磁有序的机制仍在争论中。在这里，我们提出了单层CrI 3中铁磁性的微观轨道解析描述。从第一性原理计算开始，我们为各向同性海森堡交换相互作用构建了一个低能模型。我们发现CrI 3中的远距离磁有两个相互竞争的贡献：（i）半填充的t 2 g Cr原子轨道之间的反铁磁Anderson超交换；