Zhang Zhiwang, Gao Penglin, Liu Wenjie, Yue Zichong, Cheng Ying, Liu Xiaojun, Christensen Johan
Department of Physics, MOE Key Laboratory of Modern Acoustics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, 210093, Nanjing, China.
State Key Laboratory of Mechanical System and Vibration, School of Mechanical Engineering, Shanghai Jiao Tong University, 200240, Shanghai, China.
Nat Commun. 2022 Aug 30;13(1):5096. doi: 10.1038/s41467-022-32777-0.
A single-wall carbon nanotube can be viewed as a one-dimensional material created by rolling up a sheet of graphene. Its electronic band structure depends on the chirality, i.e., how the sheet has been rolled up, yet synthesizing the symmetry at will is rather challenging. We structure an artificial honeycomb lattice in both a zigzag and an armchair tube and explore their topological features for sound. Our findings reveal how armchair tubes remain gapless, whereas the zigzag counterparts host nontrivial edge states of non-zero quantized Zak phase, which are dictated by the circumferential number of units. Unlike man-made planar lattices whose underling symmetry must be broken to harvest quantum Hall and pseudospin phases, interestingly, the structured tubular lattice symmetry remains intact, while its nontrivial phase alone is governed by the chirality and the tube diameter. We foresee that our results, not only for sound, but also in photonics, mechanics and electronics will broaden future avenues for fundamental and applied sciences.
单壁碳纳米管可被视为通过卷起一层石墨烯而形成的一维材料。其电子能带结构取决于手性，即该层是如何卷起的，然而随意合成这种对称性颇具挑战性。我们在锯齿形和扶手椅形碳纳米管中构建了人工蜂窝晶格，并探索它们的声学拓扑特征。我们的研究结果揭示了扶手椅形碳纳米管如何保持无带隙状态，而锯齿形碳纳米管则具有非平凡的边缘态，其具有非零的量子化扎克相位，这由圆周单元数决定。与人工平面晶格不同，其基础对称性必须被打破才能获得量子霍尔相和赝自旋相，有趣的是，结构化的管状晶格对称性保持完整，而其非平凡相仅由手性和管径决定。我们预见，我们的结果不仅适用于声学，还适用于光子学、力学和电子学，将为基础科学和应用科学拓宽未来的道路。
