The discovery of intrinsic two-dimensional magnetism has ignited intense research interest due to the several and attractive applications in spintronics. ${\mathrm{Nb}}_3{\mathrm{I}}_8$ is a recently investigated van der Waals material, exhibiting ferromagnetism and extraordinary visible light-harvesting ability in monolayer form, besides useful remarkable features for the realization of future high-performance nanodevices. Here we use density functional theory and classical Monte Carlo simulations to investigate the electronic and magnetic properties of ${\mathrm{Nb}}_3{\mathrm{I}}_8$ in bulk, monolayer, and some multilayer (bilayer and trilayer) forms. Two suitable vdW exchange-correlation functionals, $\mathsf{vdW-DF2-C09}$ and $\mathsf{rev-vdW-DF2}$, have been chosen to compare the first-principles calculation predictions. The layer number directly influences the ground-state magnetism, indicating the possibility of using the thickness as a parameter to control the magnetic response of the material. In particular, it is possible to switch on the antiferromagnetism by adding one or two layers to the ferromagnetic monolayer. This makes ${\mathrm{Nb}}_3{\mathrm{I}}_8$ an excellent platform for spintronics applications. Monte Carlo simulations based on a third-nearest-neighbor Ising model provide a Curie temperature close to room temperature ($\sim 307$ K) for the monolayer. The results on the electronic and magnetic properties render the two-dimensional ${\mathrm{Nb}}_3{\mathrm{I}}_8$ an ideal and promising candidate for future research and applications.

中文翻译：

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Nb3I8的层依赖性电子和磁性

由于自旋电子学中的多种有吸引力的应用，固有的二维磁性的发现引起了强烈的研究兴趣。 ${铌}_3{\mathrm{一世}}_8$是最近研究的范德华材料，具有铁磁性和单层形式的非凡可见光收集能力，此外还具有实现未来高性能纳米器件的有用的显着特征。在这里，我们使用密度泛函理论和经典的蒙特卡洛模拟来研究电子的磁性${铌}_3{\mathrm{一世}}_8$散装，单层和一些多层（双层和三层）形式。两个合适的vdW交换关联功能，$\mathsf{vdW-DF2-C09}$ 和 $\mathsf{rev-vdW-DF2}$选择来比较第一性原理的计算预测。层数直接影响基态磁性，表明使用厚度作为控制材料的磁响应的参数的可能性。特别地，可以通过在铁磁单层上增加一层或两层来开启反铁磁性。这使得${铌}_3{\mathrm{一世}}_8$自旋电子应用的绝佳平台。基于第三近邻伊辛模型的蒙特卡洛模拟提供的居里温度接近室温（$〜307$ K）表示单层。关于电子和磁性的结果呈现二维${铌}_3{\mathrm{一世}}_8$ 未来研究和应用的理想和有希望的候选人。