Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China.
Nat Mater. 2011 Jun 26;10(8):620-4. doi: 10.1038/nmat3043.
Metamaterials can exhibit electromagnetic and elastic characteristics beyond those found in nature. In this work, we present a design of elastic metamaterial that exhibits multiple resonances in its building blocks. Band structure calculations show two negative dispersion bands, of which one supports only compressional waves and thereby blurs the distinction between a fluid and a solid over a finite frequency regime, whereas the other displays 'super anisotropy' in which compressional waves and shear waves can propagate only along different directions. Such unusual characteristics, well explained by the effective medium theory, have no comparable analogue in conventional solids and may lead to novel applications.
超材料可以表现出超越自然界的电磁和弹性特性。在这项工作中，我们设计了一种具有多个共振的弹性超材料，其构建块具有多个共振。能带结构计算显示出两个负色散带，其中一个仅支持压缩波，从而在有限的频率范围内模糊了流体和固体之间的区别，而另一个则显示出“超级各向异性”，其中压缩波和剪切波只能沿不同的方向传播。这些不寻常的特性可以用有效介质理论很好地解释，在传统固体中没有类似的类比，可能会带来新的应用。
