论文标题
振动模式和磁性顺序的小组理论研究MNBI $ _2 $ TE $ _4 $
Group theory study of the vibrational modes and magnetic order in the topological antiferromagnet MnBi$_2$Te$_4$
论文作者
论文摘要
我们采用小组理论来研究抗铁磁拓扑绝缘子MNBI $ _2 $ te $ _4 $的晶格振动和磁顺序的特性，无论是散装还是几层。在顺磁性阶段，我们获得了用于不同堆叠配置的晶状体振动模式的脱整体，选择规则和真实空间位移。我们讨论磁性如何影响这些结果。作为一个代表性的例子，我们考虑了一个双层隔层系统，并获得了晶体对称性允许的磁序形式。我们得出描述抗铁磁转变的磁磁性的允许耦合术语。最后，我们讨论结果对拉曼散射和其他光学测量的含义。我们的工作为更深入地了解晶格模式，带拓扑和MNBI $ _2 $ TE $ _4 $和其他与对称性相关的材料的磁性订单的相互作用为舞台设定了舞台。
We employ group theory to study the properties of the lattice vibrations and magnetic order in the antiferromagnetic topological insulator MnBi$_2$Te$_4$, both in bulk and few-layer form. In the paramagnetic phase, we obtain the degeneracies, the selection rules, and real-space displacements for the lattice vibrational modes for different stacking configurations. We discuss how magnetism influences these results. As a representative example, we consider a double septuple layer system and obtain the form of the magnetic order allowed by the symmetries of the crystal. We derive the allowed coupling terms that describe the paramagnetic to antiferromagnetic transition. Finally, we discuss the implications of our results for Raman scattering and other optical measurements. Our work sets the stage for a deeper understanding of the interplay of lattice modes, band topology, and magnetic order in MnBi$_2$Te$_4$ and other symmetry-related materials.
