Magnon bands in twisted bilayer honeycomb quantum magnets
Magnon bands in twisted bilayer honeycomb quantum magnets
复制标题
扭曲双层蜂窝量子磁体中的磁振子带
DOI：
10.1088/1674-1056/abeee5
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发表时间：
2021
影响因子：
1.7
通讯作者：
Feng Shiping
中科院分区：
文献类型：
--
作者：
Zhu Xingchuan;Guo Huaiming;Feng Shiping
用线性自旋波理论研究了扭曲双层蜂窝量子磁体的磁振子能带。虽然层间耦合可以是铁磁的，也可以是反铁磁的，但我们保持层内的一个铁磁，以避免可能的挫折感。对于层间铁磁的情况，我们发现磁振子带与相应的电子能谱具有相似的特征。尽管狄拉克点附近的线性色散被保留在扭曲双层磁体的磁振子带中，但它们的斜率随着扭转角的减小而减小。另一方面，层间反铁磁耦合产生了完全不同的磁振子谱。由于两层中的自旋方向相反，两个单层磁振子谱通常是解耦的。我们还发展了一个适用于极小扭角的低能连续理论，该理论已被证实与严格紧束缚计算很好地吻合。由于二维磁性材料的快速发展，我们的结果可以在实验上观察到。
We study the magnon bands of twisted bilayer honeycomb quantum magnets using linear spin wave theory. Although the interlayer coupling can be ferromagnetic or antiferromagnetic, we keep the intralayer one ferromagnetic to avoid possible frustration. For the interlayer ferromagnetic case, we find the magnon bands have similar features with the corresponding electronic energy spectrums. Although the linear dispersions near the Dirac points are preserved in the magnon bands of twisted bilayer magnets, their slopes are reduced with the decrease of the twist angles. On the other hand, the interlayer antiferromagnetic couplings generate quite different magnon spectra. The two single-layered magnon spectra are usually decoupled due to the opposite orientations of the spins in the two layers. We also develop a low-energy continuous theory for very small twist angles, which has been verified to fit well with the exact tight-binding calculations. Our results may be experimentally observed due to the rapid progress in two-dimensional magnetic materials.