Two-dimensional (2D) intrinsic ferromagnetic (FM) materials with high Curie temperatures (Tc), large perpendicular magnetic anisotropy (PMA), and large spin polarization are desirable for atomically thin spintronic devices. Herein, we propose a 2D intrinsic FM material Mn2GeI2 monolayer with thermodynamical stability and outstanding FM properties using first-principles calculations. Our calculations show that Mn2GeI2 monolayer is a half-metal with a spin gap of 1.76 eV, which ensures 100% spin polarization ratio at the Fermi level. Importantly, Mn2GeI2 monolayer has a large PMA energy of 2.90 meV and a high Tc of 648 K, ideal for practical applications at room temperature. Further in-depth investigation of microscopic coupling in the Mn2GeI2 monolayer reveals that the robust ferromagnetism mainly resulted from the synthetic effect of Ruderman–Kittel–Kasuya–Yosida exchange interaction between the Mn ion layers and superexchange interaction within the Mn ion layers. Our results give insights into the structure and electronic and magnetic properties of Mn2GeI2 monolayer and provide a promising candidate for 2D spintronic devices.

中文翻译：

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高居里温度、大垂直磁各向异性的半金属Mn2GeI2单层

具有高居里温度 (Tc)、大垂直磁各向异性 (PMA) 和大自旋极化的二维 (2D) 本征铁磁 (FM) 材料是原子薄自旋电子器件所需要的。在此，我们利用第一性原理计算提出了一种具有热力学稳定性和出色的调频性能的二维本征调频材料 Mn2GeI2 单层。我们的计算表明，Mn2GeI2单层是一种半金属，自旋间隙为1.76 eV，这保证了费米能级上100%的自旋极化率。重要的是，Mn2GeI2单层具有2.90 meV的高PMA能量和648 K的高Tc，非常适合室温下的实际应用。对Mn2GeI2单层微观耦合的进一步深入研究表明，强铁磁性主要来自Mn离子层之间的Ruderman-Kittel-Kasuya-Yosida交换相互作用和Mn离子层内的超交换相互作用的综合效应。我们的研究结果深入了解了 Mn2GeI2 单层的结构以及电子和磁性特性，并为二维自旋电子器件提供了有希望的候选材料。