Yin Zhengyu, Zhou Baozeng
Tianjin Key Laboratory of Film Electronic & Communicate Devices, School of Integrated Circuit Science and Engineering, Tianjin University of Technology, Tianjin 300384, China.
Phys Chem Chem Phys. 2024 Jul 3;26(26):18382-18393. doi: 10.1039/d4cp01407c.
Compared with ferromagnetic (FM) materials, antiferromagnetic (AFM) materials have the advantages of not generating stray fields, resisting magnetic field disturbances, and displaying ultrafast dynamics and are thus considered as ideal candidate materials for next-generation high-speed and high-density magnetic storage. In this study, a new AFM device was constructed based on density functional theory calculations through the formation of a CrBr/CaN van der Waals heterostructure. The FM ground state in CrBr undergoes an AFM transition when combining with the electride CaN. In such a system, since the metal Ca atoms form the exposed layer in the electride, the heterostructure interface has a high binding energy and a large amount of charge transfer. However, for individual electron doping, the FM ground state in the CrBr monolayer is robust. Therefore, the main factor in magnetic phase transition is the interface orbital coupling caused by the strong binding energy. Furthermore, the interface coupling effect was revealed to be a competition between direct exchange and superexchange interactions. Additionally, different pathways of orbital hybridization cause a transition of the magnetic anisotropy from out-of-plane to in-plane. This work not only provides a feasible strategy for changing the ground state of magnetic materials on electride substrates but also brings about more possibilities for the construction and advancement of new AFM devices.
与铁磁（FM）材料相比，反铁磁（AFM）材料具有不产生杂散场、抗磁场干扰以及展现超快动力学等优点，因此被视为下一代高速高密度磁存储的理想候选材料。在本研究中，基于密度泛函理论计算，通过形成CrBr/CaN范德华异质结构构建了一种新型AFM器件。当CrBr与电子化合物CaN结合时，其FM基态会发生AFM转变。在这样的体系中，由于金属Ca原子在电子化合物中形成暴露层，异质结构界面具有高结合能和大量电荷转移。然而，对于单个电子掺杂，CrBr单层中的FM基态是稳定的。因此，磁相变的主要因素是由强结合能引起的界面轨道耦合。此外，界面耦合效应表现为直接交换和超交换相互作用之间的竞争。另外，不同的轨道杂化途径导致磁各向异性从面外转变为面内。这项工作不仅为改变电子化合物衬底上磁性材料的基态提供了一种可行策略，也为新型AFM器件的构建和发展带来了更多可能性。
