The study on two-dimensional (2D) magnetic materials attracts extensive research interest. Nonetheless, it is rare to find reports on heterostructures. Thus, we investigated the magnetic properties of a 2D VI₃/CrI₃ heterostructure under the external pressure. Without spin–orbit coupling (SOC), VI₃/CrI₃ had a direct band gap of 0.91 eV, and an indirect band gap of 0.98 eV appeared at 1.65 GPa. With SOC, the band gap was decreased to 0.56 eV, and the direct band gap feature remained even under the pressure. We obtained a perpendicular magnetic anisotropy energy of 0.4 meV/cell, and the major contribution originated from the interface iodine atoms. We also found a Curie temperature of 90 K, and this is almost twice the monolayer structures of both VI₃ and CrI₃. Besides, we found a large valley splitting of 21 meV, and this was further enhanced to 28 meV at 1.65 GPa. Particularly, the conduction band minimum and valence band maximum appeared in two different layers. This may suggest that a relatively long lifetime valley exciton can be observed in this VI₃/CrI₃ heterostructure bilayer.

中文翻译：

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二维VI ₃ / CrI ₃异质结构中的大谷裂和居里温度的提高

二维（2D）磁性材料的研究引起了广泛的研究兴趣。但是，很少有关于异质结构的报告。因此，我们研究了在外部压力下2D VI ₃ / CrI ₃异质结构的磁性。无自旋轨道耦合（SOC），VI ₃ / CrI ₃的直接带隙为0.91 eV，在1.65 GPa处出现的间接带隙为0.98 eV。使用SOC时，带隙减小到0.56 eV，即使在压力下，直接带隙特征也保持不变。我们获得了0.4 meV / cell的垂直磁各向异性能，并且主要的贡献来自于界面上的碘原子。我们还发现居里温度为90 K，这几乎是VI ₃和CrI ₃的单层结构的两倍。此外，我们发现了一个21 meV的大谷值分裂，并在1.65 GPa时进一步增强到28 meV。特别地，导带最小值和价带最大值出现在两个不同的层中。这可能表明在该VI ₃ / CrI中可以观察到较长的寿命谷激子。₃异质结构双层。