Curie temperature of emerging two-dimensional magnetic structures
Curie temperature of emerging two-dimensional magnetic structures
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DOI：
10.1103/physrevb.100.205409
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发表时间：
2019-11-07
影响因子：
3.7
通讯作者：
Yang, Li
中科院分区：
文献类型：
--
作者：
Lu, Xiaobo;Fei, Ruixiang;Yang, Li
二维货车德瓦耳斯材料的内禀长程磁序的研究引起了人们极大的兴趣。在这项工作中，我们采用XXZ海森堡模型和蒙特卡罗模拟研究这些新兴的二维磁性材料的基本性质，居里温度（Tc）。通过包括从第一性原理模拟中提取的现场和邻居耦合，我们已经计算了单层三卤化铬和Cr2 Ge 2 Te 6，这是目前广泛关注的T-c，模拟结果与现有的测量结果一致。我们还阐明了各向异性和各向同性相互作用在决定磁序Tc中所起的作用。特别是，我们发现一个普遍的，线性的依赖关系T-C和磁相互作用的参数空间内的现实材料。有了这种线性关系，我们可以预测一般的二维晶格结构的T-c，省略蒙特卡罗模拟。与广泛使用的伊辛模型、平均场理论和自旋波理论相比，这项工作提供了一个方便和定量的T-c估计，为加速寻找具有更高居里温度的新型2D材料带来了希望。
Recent realizations of intrinsic, long-range magnetic orders in two-dimensional (2D) van der Waals materials have ignited tremendous research interest. In this work, we employ the XXZ Heisenberg model and Monte Carlo simulations to study a fundamental property of these emerging 2D magnetic materials, the Curie temperature (T-c). By including both on-site and neighbor couplings extracted from first-principles simulations, we have calculated T-c of monolayer chromium trihalides and Cr2Ge2Te6, which are of broad interest currently, and the simulation results agree with available measurements. We also clarify the roles played by anisotropic and isotropic interactions in deciding T-c of magnetic orders. Particularly, we find a universal, linear dependence between T-c and magnetic interactions within the parameter space of realistic materials. With this linear dependence, we can predict T-c of general 2D lattice structures, omitting the Monte Carlo simulations. Compared with the widely used Ising model, mean-field theory, and spin-wave theory, this work provides a convenient and quantitative estimation of T-c, giving hope to speeding up the search for novel 2D materials with higher Curie temperatures.