Zhao Mingyu, Dai Xianqi, Tang Yanan
School of Physics, Southeast University, Nanjing 211189, China.
School of Physics, Henan Normal University, Henan 453000, China.
Phys Chem Chem Phys. 2020 Sep 23;22(36):20477-20481. doi: 10.1039/d0cp03406a.
Magnetic ordering in two-dimensional materials with atomic level thickness has been one of the most important issues in condensed matter physics and material science. Most previous studies have focused on the two-dimensional ferromagnetic systems, while the antiferromagnetic systems have been much less touched. Here, by using first-principles calculations and Monte Carlo simulation, a two-dimensional antiferromagnetic heterojunction: CrCl3/[Mo2C(-O)]2, is predicted, by tuning the electronic distribution. The ferromagnetic coupling between the Cr-Cr atoms in the CrCl3/(Mo2C)2 heterostructure is enhanced by the transferred electrons from Mo2C, which will occupy the t2g orbits of Cr. With the O adsorbed on the Mo2C, the Cr-Cl bond length increases and the superexchange interaction is decreased. The magnetic ground state changes to antiferromagnetism. More interestingly, under a moderate compressive biaxial strain, its Néel temperature of CrCl3/(Mo2C-O)2 can be significantly increased for the enhanced direct exchange of Cr-Cr atom with a value of 146 K. The heterojunction is useful for two-dimensional spintronic logic, ultrafast magnetodynamic devices and information storage for new generation computer devices.
具有原子级厚度的二维材料中的磁有序一直是凝聚态物理和材料科学中最重要的问题之一。此前的大多数研究都集中在二维铁磁系统上，而反铁磁系统则很少受到关注。在此，通过第一性原理计算和蒙特卡罗模拟，通过调节电子分布，预测了一种二维反铁磁异质结：CrCl3/[Mo2C(-O)]2。CrCl3/(Mo2C)2异质结构中Cr-Cr原子之间的铁磁耦合通过从Mo2C转移来的电子得到增强，这些电子将占据Cr的t2g轨道。当O吸附在Mo2C上时，Cr-Cl键长增加，超交换相互作用减弱。磁基态转变为反铁磁性。更有趣的是，在适度的双轴压缩应变下，由于Cr-Cr原子直接交换增强，CrCl3/(Mo2C-O)2的奈尔温度可显著提高，达到146 K。该异质结可用于二维自旋电子逻辑、超快磁动力学器件以及新一代计算机设备的信息存储。
