Searching for two-dimensional (2D) magnetic materials with high critical temperature and intrinsic magnetism have attracted significant research interests recently. By using swarm-intelligence structure search and first-principles calculations, we predict two low-energy MnB₆ monolayers, namely MnB₆-I and MnB₆-II, with high stabilities and intriguing electronic and magnetic properties. Specifically, the phonon spectrum and ab initio molecular dynamics simulations indicate the two sheets are dynamically and thermally stable. The MnB₆-I and MnB₆-II layers are both metallic with ferromagnetic (FM) and antiferromagnetic (AFM) ground state, respectively. When spin-orbital coupling is considered, the type-II Dirac points and a sizable magnetocrystalline anisotropy energy (938 $\mu \text{eV}$ per Mn atom) can be found in the MnB₆-I sheet. The Monte Carlo simulation based on the Heisenberg model suggests the Curie temperature for MnB₆-I sheet is up to 470 K, which is above room temperature. The superior electronic and magnetic properties of the MnB₆ monolayers render them promising candidates for spintronic applications.

寻找具有高临界温度和固有磁性的二维 (2D) 磁性材料最近引起了重大的研究兴趣。通过使用群体智能结构搜索和第一性原理计算，我们预测了两种低能 MnB ₆单分子层，即 MnB ₆ -I 和 MnB ₆ -II，具有高稳定性和有趣的电子和磁性。具体而言，声子光谱和从头算分子动力学模拟表明这两个片层是动态和热稳定的。MnB ₆ -I 和 MnB ₆-II 层分别是具有铁磁 (FM) 和反铁磁 (AFM) 基态的金属。当考虑自旋轨道耦合时，II 型狄拉克点和相当大的磁晶各向异性能量 (938$\mu \text{电动汽车}$每个 Mn 原子）可以在 MnB ₆ -I 表中找到。基于海森堡模型的蒙特卡罗模拟表明，MnB ₆ -I 片材的居里温度高达 470 K，高于室温。MnB ₆单层的优异电子和磁性特性使其成为自旋电子应用的有希望的候选者。