AI 中文总结
该研究在二维反常磁体中预测了由镜像对称性保护、边缘模式动量分离的II型镜像陈绝缘体，提出PbSe/$\text{V}_2\text{Se}_2\text{O}$异质双层为候选实现材料，拓展了拓扑相的实现途径。
AI 中文摘要
具有零净磁化强度但存在动量依赖自旋分裂的反常磁体，在时间反演对称性破缺时可支撑独特的拓扑态。我们在二维反常磁体中预测了一种由镜像对称性保护的拓扑晶体绝缘体，其具有动量分离的边缘模式。利用方-八角晶格模型，我们证明反常磁序会产生与对称性相关的谷极化狄拉克节点，这些节点在自旋轨道耦合作用下打开能隙，形成镜像陈数为$C_{\text{mathcal{M}}}=2$的镜像陈绝缘体。与常规镜像陈绝缘体中两个镜像保护的边缘模式在同一动量处交叉形成狄拉克锥不同，反常磁体的自旋分裂和谷选择的带反转会将这些边缘模式在动量上分离，我们将这一相称为II型镜像陈绝缘体。我们进一步提出PbSe/$\text{V}_2\text{Se}_2\text{O}$异质双层作为候选材料，可通过反常磁邻近效应实现该相。我们的结果确立了反常磁性作为实现具有动量分离边缘模式的镜像保护拓扑相的一条途径。
英文摘要
Altermagnets with momentum-dependent spin splitting despite zero net magnetization can support unique topological states under broken time-reversal symmetry. We predict a mirror-symmetry-protected topological crystalline insulator with momentum-separated edge modes in a two-dimensional altermagnet. Using a square-octagon lattice model, we show that altermagnetic order generates symmetry-related valley-polarized Dirac nodes, which are gapped by spin-orbit coupling to yield a mirror Chern insulator with $C_{\mathcal{M}}=2$. In contrast to conventional mirror Chern insulators, where the two mirror-protected edge modes cross at the same momentum to form a Dirac cone, altermagnetic spin splitting and valley-selective band inversion separate these edge modes in momentum. We refer to this phase as a type-II mirror Chern insulator. We further propose a PbSe/$\mathrm{V_2Se_2O}$ heterobilayer as a candidate material for realizing this phase through the altermagnetic proximity effect. Our results establish altermagnetism as a route to mirror-protected topological phases with momentum-separated edge modes.
Comments6 pages, 4 figures
