Jiang Jiawei, Li Rui, Mi Wenbo
Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparation Technology, School of Science, Tianjin University, Tianjin, 300354, China.
Mater Horiz. 2022 Oct 31;9(11):2785-2796. doi: 10.1039/d2mh00888b.
The modulation of exchange interactions in layered magnets has fundamental research value and potential applications in spintronics. Based on first-principles calculations, the exchange interactions in the experimentally controversial room-temperature ferromagnetic 1T-VSe monolayer are systematically studied. It is found that three shells of nearest-neighbor Heisenberg exchange interactions and higher-order interactions are crucial for an accurate description of the magnetism and its thermal stability in the 1T-VSe monolayer. Based on our understanding of tuning the magnetic interactions and the magnetic ground state in the 1T-VSe monolayer external factors, two modulation methods, involving adsorption of the alkali metal lithium and the electride CaN substrate, are proposed. In both Li-VSe and VSe/CaN systems, the strongly frustrated Heisenberg exchange interaction competes with the Dzyaloshinskii-Moriya interaction and magnetocrystalline anisotropy, leading to complex magnetic ground states, such as antiferromagnetic spin spiral and periodic antiferromagnetic cycloidal states. Moreover, the higher-order exchange interactions play a crucial role in the stabilization of long-range double-row-wise antiferromagnetic states in Li-VSe and VSe/CaN. These results highlight the effective manipulation of exchange interactions in two-dimensional magnets.
层状磁体中交换相互作用的调制在自旋电子学中具有基础研究价值和潜在应用。基于第一性原理计算，对实验上存在争议的室温铁磁1T-VSe单层中的交换相互作用进行了系统研究。研究发现，最近邻海森堡交换相互作用的三个壳层以及高阶相互作用对于准确描述1T-VSe单层中的磁性及其热稳定性至关重要。基于我们对调控1T-VSe单层中磁相互作用和磁基态的理解，提出了两种调制方法，包括碱金属锂的吸附和电子化合物CaN衬底。在Li-VSe和VSe/CaN系统中，强受挫的海森堡交换相互作用与Dzyaloshinskii-Moriya相互作用和磁晶各向异性相互竞争，导致复杂的磁基态，如反铁磁自旋螺旋和周期性反铁磁摆线态。此外，高阶交换相互作用在Li-VSe和VSe/CaN中长程双行反铁磁态的稳定中起着关键作用。这些结果突出了二维磁体中交换相互作用的有效调控。
