Yan Liang, Wang Zhigang, Yan Jie-Yun
School of Science, Beijing University of Posts and Telecommunications, Beijing 100876, People's Republic of China.
Institute of Applied Physics and Computational Mathematics, Beijing 100088, People's Republic of China.
J Phys Condens Matter. 2024 Jun 7;36(35). doi: 10.1088/1361-648X/ad512a.
Higher-order topological states extend the power of nontrivial topological states beyond the bulk-edge correspondence. Here we study the higher-order topological states (corner states) in an open-boundary two-dimensional T-graphene lattice. Unlike the common zero-energy corner states, our findings reveal non-zero energy corner states in such lattice systems, and the energy could be controlled by modifying the hopping parameters. Moreover, the corner states could be transferred away from the lattice corners by designing the position-specific vacancy defects. The strong robustness of the corner states is also demonstrated against the uniaxial strain and vacancy defects, respectively. A plasmonic crystal is constructed to testify to the theory, in which the corner states are realized in optical modes and their higher-order topological properties are verified. Our results open the avenue of corner-states engineering, which holds significant physical implications of higher-order topological states for the design of photonic and electronic devices with specialized functionalities.
高阶拓扑态将非平凡拓扑态的能力扩展到了体边对应之外。在此，我们研究开放边界二维T型石墨烯晶格中的高阶拓扑态（角态）。与常见的零能角态不同，我们的研究结果揭示了此类晶格系统中的非零能角态，并且能量可通过修改跳跃参数来控制。此外，通过设计特定位置的空位缺陷，角态可从晶格角转移开。角态分别针对单轴应变和空位缺陷也表现出很强的鲁棒性。构建了一个等离子体晶体来验证该理论，其中角态在光学模式中得以实现，并验证了它们的高阶拓扑性质。我们的结果开辟了角态工程的途径，这对于具有特定功能的光子和电子器件设计具有高阶拓扑态的重要物理意义。
