论文标题
边缘在准晶体模型中的作用
Role of the edges in a quasicrystalline Haldane model
论文作者
论文摘要
我们研究边缘在确定拓扑阶段在准晶体高阶拓扑绝缘子中的作用。我们考虑了一个特定的模型，该模型由两个堆叠的Haldane模型组成，具有相反的Chern数字和$ 30^\ Circ $ Twist，其结构在结构上与石墨烯准晶体相当。我们发现，当考虑到不同种类的边缘时，高阶拓扑绝缘子的低能拓扑谱中的间隙开放发生在不同的能量。至关重要的是，胡须键似乎是差距看起来接近电荷中立点的必要条件。在更现实的锯齿形边缘的情况下，间隙在电子和孔区域对称开放，远离零能量。我们通过在准周期性的近似中检查脱钩双层的边缘带来的边缘波带来解释我们的发现。
We study the role of the edges in determining the features of the topological phase in a quasicrystalline higher order topological insulator. We consider a specific model consisting of two stacked Haldane models with opposite Chern number and a $30^\circ$ twist, whose structure is crystallographically equivalent to that of the graphene quasicrystal. We find that the gap-opening in the low energy spectrum of the higher order topological insulator occurs at different energies when different kinds of edges are considered. Crucially, bearded bonds appear to be necessary for the gap to appear close to the charge neutrality point. In the more realistic case of zigzag edges, the gap opens symmetrically in the electron and hole sectors, away from zero energy. We explain our findings by inspecting the edge-bands of the decoupled bilayer, in the approximation of quasi-periodicity.
