摘要
Metamaterials with higher-order topological band gaps that exhibit topological physics beyond the bulkedge correspondence provide unique application values due to their ability of integrating topological boundary states at multiple dimensions in a single chip.On the other hand,in the past decade,micromechanical metamaterials are developing rapidly for various applications such as micro-piezoelectricgenerators,intelligent micro-systems,on-chip sensing and self-powered micro-systems.To empower these cutting-edge applications with topological manipulations of elastic waves,higher-order topological mechanical systems working at high frequencies(MHz)with high quality-factors are demanded.The current realizations of higher-order topological mechanical systems,however,are still limited to systems with large scales(centimetres)and low frequencies(k Hz).Here,we report the first experimental realization of an on-chip micromechanical metamaterial as the higher-order topological insulator for elastic waves at MHz.The higher-order topological phononic band gap is induced by the band inversion at the Brillouin zone corner which is achieved by configuring the orientations of the elliptic pillars etched on the silicon chip.With consistent experiments,theory and simulations,we demonstrate the emergence of coexisting topological edge and corner states in a single silicon chip as induced by the higher-order band topology.The experimental realization of on-chip micromechanical metamaterials with higherorder topology opens a new regime for materials and applications based on topological elastic waves.
高阶拓扑超材料具有多个维度拓扑态,拓展了人们对经典波体系体边对应的理解.另一方面,微机械系统在众多领域具有广泛应用,如声表面波器件、陀螺传感器、微镜整列等.声表面波器件在手机等通讯系统中不可或缺,但它的性能主要受基底材料和插齿电极构型限制.为了增强声表面波等微机械系统的性能,需要制备具有高频率、高品质因数的高阶拓扑微机械系统.然而目前高阶拓扑机械系统仍局限于大尺度和低频.本文基于硅片材料实现了弹性波高阶拓扑绝缘体,首先通过调节角度实现能带反转并得到高阶拓扑带隙,接着通过微加工制备了具有一阶拓扑边缘态和零阶拓扑角态的硅片器件.高阶拓扑微机械超材料的实现,为拓扑弹性波超材料在声表面波器件中的应用提供了新的途径.
作者
Ying Wu
Mou Yan
Zhi-Kang Lin
Hai-Xiao Wang
Feng Li
Jian-Hua Jiang
吴迎;严谋;林志康;王海啸;李锋;蒋建华(School of Physics and Optoelectronics,South China University of Technology,Guangzhou 510640,China;School of Physical Science and Technology&Collaborative Innovation Center of Suzhou Nano Science and Technology,Soochow University,Suzhou 215006,China;School of Physical Science and Technology,Guangxi Normal University,Guilin 541004,China;Key Lab of Advanced Optoelectronic Quantum Architecture and Measurement(MOE)and School of Physics,Beijing Institute of Technology,Beijing 100081,China;Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province&Key Lab of Modern Optical Technologies of Education Ministry of China,Soochow University,Suzhou 215006,China)
基金
supported by the Natural Science Foundation of Guangdong Province(2020A1515010549)
China Postdoctoral Science Foundation(2020M672615 and 2019M662885)
National Postdoctoral Program for Innovative Talents(BX20190122)
the Jiangsu specially-appointed professor funding。
