Two-dimensional van der Waals (vdW) magnetic materials are well-recognized milestones toward nanostructured spintronics. An interesting example is CrI₃; its magnetic states can be modulated electrically, allowing spintronics applications that are highly compatible with electronics technologies. Here, we report the electric field alone induces the interlayer antiferromagnetic-to-ferromagnetic (AFM-to-FM) phase transition in CrI₃ bilayers with critical field as low as 0.12 V/Å. The AFM-FM energy difference ΔE increases with electric field and is closely related to the field-induced on-site energy difference defined as the splitting between the electronic states of the two vdW layers. Our tight-binding model fits closely with ΔE as a function of electric field and gives a consistent estimation for orbital hopping, exchange splitting, and crystal field splitting. Furthermore, a CrI₃-based spin field-effect device is suggested with the spin current switched on and off solely by the electric field. These findings not only reveal the physics underlying the transition but also provide guidelines for future discovery and design.

中文翻译：

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范德华CrI ₃双层中的电场调制磁相变

二维范德华（vdW）磁性材料是纳米结构自旋电子学的公认里程碑。CrI ₃是一个有趣的例子。它的磁态可以电调制，从而使自旋电子学应用与电子技术高度兼容。在这里，我们报道电场仅在CrI ₃双层中感应出层间反铁磁到铁磁（AFM-FM）相变，临界场低至0.12 V /Å。AFM-FM能量差ΔE随着电场的增加而增加，并与定义为两个vdW层电子状态之间分裂的场感应现场能量差密切相关。我们的紧密绑定模型与ΔE非常吻合作为电场的函数，并给出了对轨道跳跃，交换分裂和晶体场分裂的一致估计。此外，提出了基于CrI ₃的自旋场效应器件，其中仅通过电场来接通和关断自旋电流。这些发现不仅揭示了过渡过程的物理基础，而且为将来的发现和设计提供了指导。