Yang Jikun, Li Zhanmiao, Xin Xudong, Gao Xiangyu, Yuan Xiaoting, Wang Zehuan, Yu Zhonghui, Wang Xiaohui, Zhou Ji, Dong Shuxiang
Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing 100871, China.
State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China.
Sci Adv. 2019 Nov 8;5(11):eaax1782. doi: 10.1126/sciadv.aax1782. eCollection 2019 Nov.
Designing topological and geometrical structures with extended unnatural parameters (negative, near-zero, ultrahigh, or tunable) and counterintuitive properties is a big challenge in the field of metamaterials, especially for relatively unexplored materials with multiphysics coupling effects. For natural piezoelectric ceramics, only five nonzero elements in the piezoelectric matrix exist, which has impeded the design and application of piezoelectric devices for decades. Here, we introduce a methodology, inspired by quasi-symmetry breaking, realizing artificial anisotropy by metamaterial design to excite all the nonzero elements in contrast to zero values in natural materials. By elaborately programming topological structures and geometrical dimensions of the unit elements, we demonstrate, theoretically and experimentally, that tunable nonzero or ultrahigh values of overall effective piezoelectric coefficients can be obtained. While this work focuses on generating piezoelectric parameters of ceramics, the design principle should be inspirational to create unnatural apparent properties of other multiphysics coupling metamaterials.
设计具有扩展的非自然参数（负、近零、超高或可调）和反直觉特性的拓扑和几何结构是超材料领域的一项重大挑战，特别是对于具有多物理场耦合效应且相对未被充分探索的材料而言。对于天然压电陶瓷，压电矩阵中仅存在五个非零元素，这几十年来一直阻碍着压电器件的设计和应用。在此，我们引入一种受准对称性破缺启发的方法，通过超材料设计实现人工各向异性，以激发所有非零元素，而天然材料中的这些元素值为零。通过精心设计单元结构的拓扑结构和几何尺寸，我们在理论和实验上证明，可以获得可调的非零或超高的整体有效压电系数值。虽然这项工作专注于生成陶瓷的压电参数，但该设计原理对于创造其他多物理场耦合超材料的非自然表观特性应具有启发性。
