论文标题
二维拓扑绝缘子的工程角状态
Engineering Corner States from Two-Dimensional Topological Insulators
论文作者
论文摘要
从理论上讲，我们可以通过应用平面内的Zeeman领域来证明，具有稳健角状态的二阶拓扑绝缘子可以在二维$ \ Mathbb {z} _2 $拓扑绝缘器中实现。 Zeeman Field打破了时间反转对称性，从而破坏了$ \ Mathbb {Z} _2 $拓扑阶段。然而，它尊重某些结晶对称性，因此可以保护高阶拓扑阶段。通过以Kane-Mele模型为具体的示例，我们发现沿着锯齿形边界的旋转边缘状态被Zeeman场所覆盖，而在两个锯齿形边缘之间的交点处的间隙角状态出现，这是独立于田间方向的。我们进一步表明，拐角状态与平面外的Zeeman领域，交错的Sublattice电位，Rashba Spin-Orbit耦合以及蜂窝晶格的屈曲，使它们在实验上可行。在著名的Bernevig-Hughes-Zhang模型中也可以找到类似的行为。
We theoretically demonstrate that the second-order topological insulator with robust corner states can be realized in two-dimensional $\mathbb{Z}_2$ topological insulators by applying an in-plane Zeeman field. Zeeman field breaks the time-reversal symmetry and thus destroys the $\mathbb{Z}_2$ topological phase. Nevertheless, it respects some crystalline symmetries and thus can protect the higher-order topological phase. By taking the Kane-Mele model as a concrete example, we find that spin-helical edge states along zigzag boundaries are gapped out by Zeeman field whereas in-gap corner state at the intersection between two zigzag edges arises, which is independent on the field orientation. We further show that the corner states are robust against the out-of-plane Zeeman field, staggered sublattice potentials, Rashba spin-orbit coupling, and the buckling of honeycomb lattices, making them experimentally feasible. Similar behaviors can also be found in the well-known Bernevig-Hughes-Zhang model.
