论文标题
二维范德华磁性半导体异质结构中居里温度和磁各向异性的大大增强
Great enhancement of Curie temperature and magnetic anisotropy in two-dimensional van der Waals magnetic semiconductor heterostructures
论文作者
论文摘要
在二维（2D）磁系统中，根据Mermin-Wagner定理稳定磁性需要大的磁各向异性。基于密度功能理论（DFT）计算，我们提出，2D铁磁（FM）半导体的磁各向异性能量（MAE）可以通过将非磁性半导体单层与大型Spin-Orbit couppling一起连接到非磁性半导体单层，从而在Van der Waals异质结构中强烈增强。我们研究了CR2GE2TE6/PTSE2双层异质结构，在最近的实验中已经实现了每一层。 DFT计算表明，CR2GE2TE6/PTSE2的MAE增强了70％，而Curie温度TC的增加远远超出了室温。建议哈密顿模型分析DFT结果，表明Dzyaloshinskii-Moriya的相互作用和单离子各向异性都有助于增强MAE。基于超级交换图，我们发现CR的3D轨道和TE的5p轨道之间的能量差减少对TC的增加有所贡献。我们目前的工作表明了通过构建Van der Waals半导体异质结构来增强MAE和TC的一种有希望的方法，这将激发人们对2D磁性半导体系统的进一步研究。
In two-dimensional (2D) magnetic systems, large magnetic anisotropy is needed to stabilize the magnetic order according to Mermin-Wagner theorem. Based on density functional theory (DFT) calculations, we propose that the magnetic anisotropic energy (MAE) of 2D ferromagnetic (FM) semiconductors can be strongly enhanced in van der Waals heterostructures by attaching a nonmagnetic semiconductor monolayer with large spin-orbit coupling. We studied Cr2Ge2Te6/PtSe2 bilayer heterostructures, where each layer has been realized in recent experiments. The DFT calculations show that the MAE of Cr2Ge2Te6/PtSe2 is enhanced by 70%, and the Curie temperature TC is increased far beyond room temperature. A model Hamiltonian is suggested to analyze the DFT results, showing that both the Dzyaloshinskii-Moriya interaction and the single-ion anisotropy contribute to the enhancement of the MAE. Based on the superexchange picture, we find that the decreased energy difference between 3d orbitals of Cr and 5p orbitals of Te contributes partially to the increase of TC. Our present work indicates a promising way to enhance the MAE and TC by constructing van der Waals semiconductor heterostructures, which will inspire further studies on the 2D magnetic semiconductor systems.
