声子晶体中多频带谷选择性角态  

Multiband,valley-selective corner states in phononic crystals

作　　者：郑周甫 尹剑飞 温激鸿[1,2] 郁殿龙[1,2] 陈循[1,2] ZHENG ZhouFu;YIN JianFei;WEN JiHong;YU DianLong;CHEN Xun(Laboratory of Science and Technology on Integrated Logistics Support,National University of Defense Technology,Changsha 410073,China;College of Intelligence Science and Technology,National University of Defense Technology,Changsha 410073,China)

机构地区：[1]国防科技大学装备综合保障重点实验室,长沙410073 [2]国防科技大学智能科学学院,长沙410073

出　　处：《中国科学：技术科学》2023年第8期1313-1322,共10页Scientia Sinica(Technologica)

基　　金：国家自然科学基金(批准号:11991032,11991034)资助项目。

摘　　要：声学拓扑绝缘体具有拓扑保护、背散射及缺陷免疫的非传统声学边界态,为实现声波按需精细调控提供了一种有效的方法,其中二维高阶拓扑绝缘体中共同存在零维角态和一维边界态,使其拥有在多个维度上操纵波能量的能力,进一步增强了波调控的灵活度,引起广泛关注.本文提出了一种能够在多频带范围实现高阶拓扑态的C3对称性元胞结构,其通过旋转散射体角度激活不同谷选择性角态.这种具有开关特性的角态可以根据需求进行声波场能量局域化调控,在实际运用中具有重要意义.相对于传统的单频带高阶拓扑绝缘体,本文所设计的元胞结构能够在基频带隙和二阶高频带隙中同时实现边界态的波导调控和角态的选择性激发,并具有优秀的缺陷免疫鲁棒性.该高阶拓扑绝缘体的多频带特性将有利于拓展传统单频带器件的工作频率范围和带宽,同时角态的谷选择性激发特点可推动声学拓扑绝缘体在多波段声波能量捕获、检测和采集声学器件中的应用.Acoustic topological insulators can exhibit topologically protected acoustic boundary modes that are immune to backscattering and defects,which is an effective means for achieving fine control of acoustic waves as desired.Among these insulators,two-dimensional higher-order topological insulators share zero-dimensional corner states and one-dimensional edge states.Their acoustic manipulation capabilities in multiple dimensions have attracted increasing attention.Herein,we propose a C3-symmetric unit cell with multiband,higher-order topological states,which enables the activation of different corner states by rotating the scatters angle.These states with flexible illuminating and darkening characteristics have practical significance for wave energy localization on demand.Compared with traditional single-band higher-order topological insulators,the phononic structures designed in this study can simultaneously perform waveguide modulation of edge states and selective excitation of corner states in both fundamental and second-order bandgaps and possess defect immunity robustness.The multiband characteristics of these high-order topological insulators will be conducive to expanding the operating frequency regime and bandwidth of traditional single-band devices.Additionally,the valley-selective excitation characteristics of the corner states can promote the practical development of high-order topological insulators in multiband acoustic energy trapping,detection,and collection devices.

关 键 词：多频带角态 谷选择性激发 高阶拓扑绝缘体 拓扑相变 

分 类 号：O42[理学—声学] O469[理学—物理]