On-chip higher-order topological micromechanical metamaterials

• 作 者: Ying Wu Mou Yan Zhi-Kang Lin Hai-Xiao Wang Feng Li Jian-Hua Jiang
• 机 构: School of Physics and Optoelectronics,South China University of Technology,Guangzhou 510640,China;Sc
• 出 处: 科学通报（英文版）
• 发表日期: 2021年19期
• 关键词: Higher-order band topology Micromechanical metamaterials On-chip devices Mechani

Metamaterials with higher-order topological band gaps that exhibit topological physics beyond the bulk-edge 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,microme-chanical metamaterials are developing rapidly for various applications such as micro-piezoelectric-generators,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 cur-rent realizations of higher-order topological mechanical systems,however,are still limited to systems with large scales (centimetres) and low frequencies (kHz).Here,we report the first experimental realiza-tion 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 higher-order topology opens a new regime for materials and applications based on topological elastic waves.