Wu Dongsi, Zhao Ying, Yang Yibin, Huang Le, Xiao Ye, Chen Shanshan, Zhao Yu
School of Materials and Energy, Guangdong University of Technology, Guangzhou 510006, China.
Guangdong Provincial Key Laboratory of Information Photonics Technology, Guangdong University of Technology, Guangzhou 510006, China.
Nanomaterials (Basel). 2022 Apr 21;12(9):1420. doi: 10.3390/nano12091420.
The recent discovery of 2D magnets has induced various intriguing phenomena due to the modulated spin polarization by other degrees of freedoms such as phonons, interlayer stacking, and doping. The mechanism of the modulated spin-polarization, however, is not clear. In this work, we demonstrate theoretically and computationally that interlayer magnetic coupling of the CrI bilayer can be well controlled by intercalation and carrier doping. Interlayer atomic intercalation and carrier doping have been proven to induce an antiferromagnetic (AFM) to ferromagnetic (FM) phase transition in the spin-polarization of the CrI bilayer. Our results revealed that the AFM to FM transition induced by atom intercalation was a result of enhanced superexchange interaction between Cr atoms of neighboring layers. FM coupling induced by O intercalation mainly originates from the improved superexchange interaction mediated by Cr 3-O 2 coupling. FM coupling induced by Li intercalation was found to be much stronger than that by O intercalation, which was attributed to the much stronger superexchange by electron doping than by hole doping. This comprehensive spin exchange mechanism was further confirmed by our results of the carrier doping effect on the interlayer magnetic coupling. Our work provides a deep understanding of the underlying spin exchange mechanism in 2D magnetic materials.
二维磁体的最新发现引发了各种有趣的现象，这是由于声子、层间堆叠和掺杂等其他自由度对自旋极化的调制所致。然而，自旋极化调制的机制尚不清楚。在这项工作中，我们通过理论和计算证明，CrI双层的层间磁耦合可以通过插层和载流子掺杂得到很好的控制。层间原子插层和载流子掺杂已被证明会在CrI双层的自旋极化中诱导反铁磁（AFM）到铁磁（FM）的相变。我们的结果表明，原子插层诱导的AFM到FM转变是相邻层Cr原子之间超交换相互作用增强的结果。O插层诱导的FM耦合主要源于由Cr 3-O 2耦合介导的超交换相互作用的改善。发现Li插层诱导的FM耦合比O插层诱导的要强得多，这归因于电子掺杂比空穴掺杂的超交换要强得多。我们关于载流子掺杂对层间磁耦合影响的结果进一步证实了这种综合的自旋交换机制。我们的工作为深入理解二维磁性材料中潜在的自旋交换机制提供了帮助。
