Li Shi-Feng, Yang Wen-Jie, Zhou Cui-Yu-Yang, Zhu Yi-Fan, Zou Xin-Ye, Cheng Jian-Chun, Assouar Badreddine
Key Laboratory of Modern Acoustics, MOE, Institute of Acoustics, Department of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, P. R. China.
Jiangsu Key Laboratory for Design and Manufacture of Micro-Nano Biomedical Instruments, School of Mechanical Engineering, Southeast University, Nanjing, 211189, China.
Adv Sci (Weinh). 2025 Mar;12(10):e2409574. doi: 10.1002/advs.202409574. Epub 2025 Jan 21.
ℤ-classified higher-order topological insulators (HOTIs) with chiral-symmetric higher-order topological phases protected by multipole chiral numbers (MCNs) have attracted extensive interest recently. However, how to design artificial ℤ-classified HOTIs with multiple topological phases remains an unresolved issue. Here, multiorbital degrees of freedom are introduced to acoustic crystals and the various methods of topological phase transitions are achieved for the orbital ℤ-classified HOTIs. Experimental results demonstrate the realization the coexistence of corner modes with distinct mechanisms within one single model. This provides a pathway for finding ℤ-classified with large MCNs independent of long-range coupling. Additionally, a universal approach is introduced here to fabricate topological bound states in the continuum derived from the discrepant onsite energy of degenerate p-orbitals. These findings provide new insights into the study of topological wave physics using orbital degrees of freedom and may pave the way for designing innovative orbital topological devices for sensing and computing.
具有由多极手征数（MCN）保护的手征对称高阶拓扑相的ℤ类高阶拓扑绝缘体（HOTIs）最近引起了广泛关注。然而，如何设计具有多个拓扑相的人工ℤ类HOTIs仍然是一个未解决的问题。在此，将多轨道自由度引入声学晶体，并实现了轨道ℤ类HOTIs的各种拓扑相变方法。实验结果证明了在单个模型中实现具有不同机制的角模式共存。这为寻找与长程耦合无关的具有大MCN的ℤ类提供了一条途径。此外，这里引入了一种通用方法来制造源自简并p轨道不同在位能量的连续统中的拓扑束缚态。这些发现为利用轨道自由度研究拓扑波物理提供了新的见解，并可能为设计用于传感和计算的创新轨道拓扑器件铺平道路。
