Understanding External Pressure Effects and Interlayer Orbital Exchange Pathways in the Two-Dimensional Magnet─Chromium Triiodide
Understanding External Pressure Effects and Interlayer Orbital Exchange Pathways in the Two-Dimensional Magnet─Chromium Triiodide
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DOI：
10.1021/acs.jpcc.2c03884
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发表时间：
2022-11
期刊：
影响因子：
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通讯作者：
R. Beck;Shichao Sun;Xiaodong Xu;D. Gamelin;Ting Cao;Xiaosong Li
中科院分区：
文献类型：
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作者：
R. Beck;Shichao Sun;Xiaodong Xu;D. Gamelin;Ting Cao;Xiaosong Li
最近的实验表明，典型的范德华磁体CrI3在压力作用下经历了从高温单斜结构到低温菱形结构的相变。为了了解CrI3的磁性如何响应这些结构变化，我们对双层CrI3进行从头算密度泛函理论模拟。我们模拟了双层cri3的层间侧向位移相关的势能面，以检查稳定性和磁性作为外部压力的函数。使用混合PBE0泛函，我们能够在不使用现场库仑相互作用校正的情况下给出定性正确的交换耦合能。因此，我们避免使用可调参数。结果表明，在外部压力下，单斜晶结构比菱形晶结构更不稳定，这与在压力下观察到的少层cri3器件的相变一致。我们还研究了层间交换耦合的微观起源。我们分别确定了有利于铁磁和反铁磁动力学交换的竞争轨道路径，这与以前的报道一致。本研究开辟了利用高斯轨道杂化泛函和基于簇的方法获取HeisenbergJvalues来精确模拟二维材料磁性的新方向。
Recent experiments have shown that exfoliated few-layer CrI3, a prototypical van der Waals magnet, undergoes a phase transition from the high-temperature monoclinic structure to the low-temperature rhombohedral structure under pressure. To understand how the magnetism of CrI3responds to these structural changes, we perform ab initio density functional theory simulations on bilayer CrI3. We simulate the interlayer lateral shift-dependent potential energy surface of bilayer CrI3to examine the stability and magnetism as a function of external pressure. Using the hybrid PBE0 functional, we are able to give qualitatively correct exchange coupling energies, without using an on-site Coulomb interaction correction. Thus, we avoid using tunable parameters. The results show that under external pressure, the monoclinic crystal structure is destabilized in comparison with the rhombohedral structure, in agreement with the observed phase transition in few-layer CrI3devices under pressure. We also look into the microscopic origins of the interlayer exchange coupling. We identify the competing orbital pathways that favor ferromagnetic and antiferromagnetic kinetic exchange, respectively, which are consistent with previous reports. This study opens a new direction of using hybrid functionals with Gaussian orbitals and a cluster-based approach for obtaining HeisenbergJvalues to accurately simulate the magnetic properties of 2D materials.