We have studied topological edge states in bowtie ladders with various edge truncations. The symmetric bowtie ladder, which comprises two trivial Su–Schrieffer–Heeger (SSH) lattices, exhibits an insulator–metal transition with trivial insulating states. On the other hand, the lattice can be transformed into an extended SSH lattice depending on the edge shapes with non-trivial insulating states in that the winding number is non-zero. The winding numbers are permutationally designated in the phase diagram depending on the choice of unit cell. The topological edge states are affected by the shape of the edge and the corresponding winding number. We also studied general bowtie ladder models with richer phase diagrams using the characteristics of the localization length of the edge states showing state bifurcation.

我们已经研究了具有各种边缘截断的领结阶梯中的拓扑边缘状态。对称的蝴蝶结阶梯由两个简单的 Su-Schrieffer-Heeger (SSH) 晶格组成，表现出具有简单绝缘状态的绝缘体-金属过渡。另一方面，根据具有非平凡绝缘状态的边缘形状，由于绕组数非零，晶格可以转换为扩展的 SSH 晶格。根据单元电池的选择，绕组数在相图中排列指定。拓扑边缘状态受边缘形状和相应的绕组数的影响。我们还利用显示状态分叉的边缘状态的局部化长度的特征，研究了具有更丰富相图的一般领结阶梯模型。