由补偿交变磁性诱导的无体自旋分裂的二阶拓扑绝缘体
Second-order topological insulator induced by compensated altermagnetism without bulk spin splitting
浏览论文内容
中文总结 AI 辅助
研究在二维拓扑绝缘体薄膜中由补偿交变磁性诱导二阶拓扑绝缘相，通过引入特定交变磁项保持PT对称等，使螺旋边缘态带隙化并产生局域角态，解析相边界并构建相图，开辟无体自旋分裂的高阶拓扑途径。
中文摘要 AI 辅助
我们从理论上证明了在二维拓扑绝缘体薄膜中，由补偿交变磁性诱导出的二阶拓扑绝缘相，同时保持体能隙不变。通过在顶层和底层引入具有相反符号的层分辨面外d波交变磁项，系统保持PT对称性并在体能带中保持自旋简并，同时使螺旋边缘态带隙化并产生局域角态。所得的高阶相由非零镜分级缠绕数表征，有效的边缘理论表明角态源于狄拉克质量畴壁。我们进一步解析地确定了相边界并构建了相应的拓扑相图，建立了一条无体自旋分裂的高阶拓扑的稳健途径。
英文摘要
We theoretically demonstrate a second-order topological insulating phase induced by compensated altermagnetism, while keeping the bulk gap unchanged, in a two-dimensional topological insulator film. By introducing a layer-resolved out-of-plane $d$-wave altermagnetic term with opposite signs on the top and bottom layers, the system preserves $\mathcal{PT}$ symmetry and maintains spin degeneracy in the bulk bands, while simultaneously gapping the helical edge states and generating localized corner states. The resulting higher-order phase is characterized by nonzero mirror-graded winding numbers, and an effective edge theory shows that the corner states arise from Dirac mass domain walls. We further determine the phase boundaries analytically and construct the corresponding topological phase diagram, establishing a robust route to higher-order topology without bulk spin splitting.
