Danawe Hrishikesh, Li Heqiu, Sun Kai, Tol Serife
Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109-2125, USA.
Department of Physics, University of Michigan, Ann Arbor, Michigan 48109-2125, USA.
Phys Rev Lett. 2022 Nov 11;129(20):204302. doi: 10.1103/PhysRevLett.129.204302.
In this Letter, an elastic twisted kagome lattice at a critical twist angle, called self-dual kagome lattice, is shown to exhibit peculiar finite-frequency topological modes which emerge when certain conditions are satisfied. These states are topologically reminiscent of the zero energy (floppy) modes of Maxwell lattices, but they occur at a finite frequency in the band gap of the self-dual kagome lattice. Thus, we present a completely new class of topological modes that share similarities with both the zero frequency floppy modes in Maxwell lattices and the finite energy in-gap modes in topological insulators. We envision the presented mathematical and numerical framework to be invaluable for many technological advances pertaining to wave phenomena, such as reconfigurable waveguide designs.
在这封信中，一个处于临界扭转角的弹性扭曲戈薇晶格，即所谓的自对偶戈薇晶格，被证明在满足某些条件时会展现出奇特的有限频率拓扑模式。这些态在拓扑上让人联想到麦克斯韦晶格的零能量（软模）模式，但它们出现在自对偶戈薇晶格的带隙中的有限频率处。因此，我们提出了一类全新的拓扑模式，它既与麦克斯韦晶格中的零频率软模有相似之处，又与拓扑绝缘体中的有限能量带隙模式有相似之处。我们设想所提出的数学和数值框架对于许多与波现象相关的技术进步，如可重构波导设计，具有重要价值。
