Two-dimensional (2D) magnetic crystals are ideal platforms for the employment of simple physical models in the exploration of magnetism in a 2D limit. Instead of examining 2D van der Waals materials, the focus of our study is on adatoms that carry intrinsic magnetic moments and are assembled into 2D arrays at a suitable surface. We applied density functional theory (DFT) to investigate Fe nanostructures formed on a borophene sheet deposited at Ag(111) surface and identified stable Fe-based 2D magnets formed either on top of the borophene or at the interface between the borophene and Ag(111) surface. The structures are composed of close-packed Fe wires, featuring ferromagnetism within the chain and the interchain antiferromagnetic coupling. Exchange- and single-ion anisotropy constants extracted from DFT calculations are used to describe these systems with the classical Ising and Heisenberg models. The corresponding Monte Carlo simulations revealed finite temperature magnetic ordering, with the estimates of critical temperatures of 105 and 30 K derived from the anisotropic Heisenberg model, for the Fe-based magnets grown above and under borophene, respectively.

中文翻译：

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Ag(111)表面负载硼烯的Fe基二维磁体的Ab-initio和Monte Carlo研究

二维 (2D) 磁性晶体是使用简单物理模型探索二维极限中的磁性的理想平台。我们研究的重点不是检查二维范德华材料，而是研究携带固有磁矩并在合适表面组装成二维阵列的吸附原子。我们应用密度泛函理论 (DFT) 来研究在 Ag(111) 表面沉积的硼烯片上形成的 Fe 纳米结构，并确定了在硼烯顶部或硼烯与 Ag(111) 之间的界面处形成的稳定的 Fe 基二维磁体。 ） 表面。该结构由紧密堆积的 Fe 线组成，具有链内铁磁性和链间反铁磁耦合。从 DFT 计算中提取的交换和单离子各向异性常数用于使用经典的 Ising 和 Heisenberg 模型来描述这些系统。相应的蒙特卡罗模拟揭示了有限温度磁序，对于分别在硼烯上方和下方生长的铁基磁体，临界温度为 105 和 30 K 的估计值来自各向异性海森堡模型。