Two-dimensional (2D) ferromagnetic (FM) semiconductors with high Curie temperature have long been pursued for electronic and spintronic applications. Here we provide a general strategy to achieve robust FM state in bilayer $\mathrm{Cr}{\mathrm{I}}_3$ of the monoclinic stacking, which intrinsically has interlayer antiferromagnetic (AFM) order and weak in-plane FM coupling. We showed that the proximity effect from bulk semiconducting substrates induces electronic doping and significantly increases the FM nearest-neighbor exchange for bilayer $\mathrm{Cr}{\mathrm{I}}_3$, leading to the AFM-to-FM transition for the interlayer spin configuration as well as enhanced intralayer FM coupling. By first-principles calculations and Monte Carlo simulations, bulk and 2D semiconductors providing different interaction strengths from strong covalent bonding to weak van der Waals (vdW) interaction with $\mathrm{Cr}{\mathrm{I}}_3$ are compared to thoroughly address the substrate effect on magnetic behavior and Curie temperature of bilayer $\mathrm{Cr}{\mathrm{I}}_3$. These theoretical results offer a facile route for direct synthesis of 2D ferromagnets on proper semiconducting substrates to achieve high Curie temperature for device implementation.

中文翻译：

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块状半导体衬底上双层CrI3中的高居里温度铁磁性

居里温度高的二维（2D）铁磁（FM）半导体一直被用于电子和自旋电子应用。在这里，我们提供了在双层中实现鲁棒FM状态的一般策略$铬{\mathrm{一世}}_3$单斜堆叠的本质是层间反铁磁（AFM）阶和平面内FM耦合弱。我们表明，大块半导体衬底的邻近效应会引起电子掺杂，并显着增加双分子层的FM最近邻居交换$铬{\mathrm{一世}}_3$，导致层间自旋配置从AFM到FM过渡以及增强的层内FM耦合。通过第一性原理计算和蒙特卡洛模拟，块状和2D半导体提供了不同的相互作用强度，从强共价键结合到弱范德华（vdW）相互作用，$铬{\mathrm{一世}}_3$ 比较以彻底解决衬底对双层的磁性和居里温度的影响 $铬{\mathrm{一世}}_3$。这些理论结果为在合适的半导体衬底上直接合成2D铁磁体以实现器件实现高居里温度提供了一条简便的途径。