论文标题
高阶拓扑角状态仅由镜子对称性的现场电势引起
Higher-order topological corner states induced solely by onsite potentials with mirror symmetry
论文作者
论文摘要
高阶拓扑绝缘子引发了极大的兴趣，因为在低维边界（例如角落和铰链）上有非平凡的散装拓扑展览。尽管已经通过调整交错的隧道强度或操纵现有的拓扑阶段来研究了如此有趣的阶段，但在这里我们表明，高阶拓扑阶段可以仅由镜像 - 对称的现场电位驱动。我们首先在一个维度中引入了一个简单的链模型，该模型模仿了Su-Schrieffer-Heeger样模型。但是，由于缺乏手性或颗粒 - 孔对称性等内部对称性，拓扑边缘模式的能量并未固定为零。一旦将模型推广到两个维度，我们就会观察到拓扑角模式的出现。这些角模式是受镜子对称性保护的非平凡体积带拓扑的内在表现，因此，它们对对称性保留的扰动具有鲁棒性。我们的研究提供了一个简洁的建议，可以实现一类高阶拓扑绝缘子，这仅涉及现场能量。在实验中很容易访问，并为工程拓扑角模式提供了一个不同的操场。
Higher-order topological insulators have triggered great interests because of exhibitions of non-trivial bulk topology on lower-dimensional boundaries like corners and hinges. While such interesting phases have been investigated in a plethora of systems by tuning staggered tunneling strength or manipulating existing topological phases, here we show that a higher-order topological phase can be driven solely by mirror-symmetric onsite potentials. We first introduce a simple chain model in one dimension that mimics the Su-Schrieffer-Heeger-like model. However, due to the lack of internal symmetries like chiral or particle-hole symmetry, the energies of the topological edge modes are not pinned at zero. Once the model is generalized to two dimensions, we observe the emergence of topological corner modes. These corner modes are intrinsic manifestation of non-trivial bulk band topology protected by mirror symmetry, and thus, they are robust against symmetry-preserved perturbations. Our study provides a concise proposal for realizing a class of higher-order topological insulators, which involves only tuning onsite energies. This can be easily accessible in experiments and provides a different playground for engineering topological corner modes.
