Li Hongxing, Cheng Zi-Peng, He Bin-Guang, Zhang Wei-Bing
Hunan Provincial Key Laboratory of Flexible Electronic Materials Genome Engineering, Changsha University of Science and Technology, Changsha 410114, People's Republic of China.
Nanoscale. 2021 Mar 12;13(9):4821-4827. doi: 10.1039/d0nr07909j.
The newly discovered 2D magnetic materials provide new opportunities for basic physics research and device applications. However, their low Curie temperature (TC) is a common weakness. In this paper, by combining magnetic Hamiltonian, Wannier functions and first-principles calculations, we systematically study the magnetic properties of monolayer CrI3 functionalized with halogens. The magnetic exchange coupling (EX) and magnetic anisotropy (MA) are found to increase significantly with X (X = F, Cl and Br) atom adsorption, and increase with increased coverage of X. In the framework of superexchange theory, the enhanced EX can be ascribed to the reduced energy difference and increased hopping strength between Cr d and I p orbitals, due to the states of the I ligand engineered by the X adatom. Besides, the X adatom may provide an additional ferromagnetic superexchange channel. Our results not only give insight into understanding the enhancement of ferromagnetism of CrI3 by atom adsorption, but also propose a promising way to improve the ferromagnetism of 2D magnetic materials.
新发现的二维磁性材料为基础物理研究和器件应用提供了新机遇。然而，它们较低的居里温度（TC）是一个普遍的弱点。在本文中，通过结合磁哈密顿量、万尼尔函数和第一性原理计算，我们系统地研究了用卤素功能化的单层CrI3的磁性。发现磁交换耦合（EX）和磁各向异性（MA）随着X（X = F、Cl和Br）原子吸附而显著增加，并随着X覆盖度的增加而增加。在超交换理论框架下，增强的EX可归因于由X吸附原子设计的I配体状态导致的Cr d和I p轨道之间能量差的减小和跳跃强度的增加。此外，X吸附原子可能提供一个额外的铁磁超交换通道。我们的结果不仅有助于理解通过原子吸附增强CrI3的铁磁性，还提出了一种改善二维磁性材料铁磁性的有前景的方法。
