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Amorphous topological insulators constructed from random point sets
Nature Physics ( IF 17.6 ) Pub Date : 2018-01-15 , DOI: 10.1038/s41567-017-0024-5
Noah P. Mitchell , Lisa M. Nash , Daniel Hexner , Ari M. Turner , William T. M. Irvine

The discovery that the band structure of electronic insulators may be topologically non-trivial has revealed distinct phases of electronic matter with novel properties1,2. Recently, mechanical lattices have been found to have similarly rich structure in their phononic excitations3,4, giving rise to protected unidirectional edge modes5,6,7. In all of these cases, however, as well as in other topological metamaterials3,8, the underlying structure was finely tuned, be it through periodicity, quasi-periodicity or isostaticity. Here we show that amorphous Chern insulators can be readily constructed from arbitrary underlying structures, including hyperuniform, jammed, quasi-crystalline and uniformly random point sets. While our findings apply to mechanical and electronic systems alike, we focus on networks of interacting gyroscopes as a model system. Local decorations control the topology of the vibrational spectrum, endowing amorphous structures with protected edge modes—with a chirality of choice. Using a real-space generalization of the Chern number, we investigate the topology of our structures numerically, analytically and experimentally. The robustness of our approach enables the topological design and self-assembly of non-crystalline topological metamaterials on the micro and macro scale.



中文翻译:

由随机点集构造的非晶拓扑绝缘子

电子绝缘体的能带结构可能在拓扑上是不重要的,这一发现揭示了具有新特性1,2的电子物质的不同相。最近,已经发现机械晶格在其声子激发3,4中具有类似的丰富结构,从而产生了受保护的单向边缘模式5,6,7。然而,在所有这些情况下,以及在其他拓扑超材料中3,8,通过周期性,准周期性或等静性对基础结构进行了微调。在这里,我们显示出非晶的Chern绝缘子可以很容易地由任意下面的结构构成,包括超均匀,拥塞,准晶体和均匀随机点集。尽管我们的发现适用于机械和电子系统,但我们将交互陀螺仪网络视为模型系统。局部装饰控制了振动频谱的拓扑结构,使无定形结构具有受保护的边缘模式-可以选择手性。使用Chern数的实空间归纳,我们在数值,分析和实验上研究了我们结构的拓扑。

更新日期:2018-01-15
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