论文标题
在拓扑机械超材料中观察到开放边缘和反相边界接缝处的平坦频带
Observation of Flat Frequency Bands at Open Edges and Antiphase Boundary Seams in Topological Mechanical Metamaterials
论文作者
论文摘要
基于Su-Schrieffer-Heeger链的二维（2D）手性汉密尔顿的理论研究的动机，我们通过实验和计算表明，拓扑平面频带可以发生在2D平面层的敞开边缘，并在2D平面地层的开放式边缘发生，并在反式或无形或无类或无花体或小管的反相边界上发生。具体而言，使用由磁耦合的旋转器制成的机械系统，我们揭示了在整个投影互相空间中平坦的边缘或接缝带的存在遵循基于拓扑绕组数量的预测。边缘到边的距离灵敏地控制边缘带的平坦度和激发的定位。还观察到了分数电荷态的类似物。讨论了大量超材料（包括光子晶体和电子超材料）中平坦带的可能实现。
Motivated by the recent theoretical studies on a two-dimensional (2D) chiral Hamiltonian based on the Su-Schrieffer-Heeger chains, we experimentally and computationally demonstrate that topological flat frequency bands can occur at open edges of 2D planar metamaterials and at antiphase boundary seams of ring-shaped or tubular metamaterials. Specifically, using mechanical systems made of magnetically coupled spinners, we reveal that the presence of the edge or seam bands that are flat in the entire projected reciprocal space follows the predictions based on topological winding numbers. The edge-to-edge distance sensitively controls the flatness of the edge bands and the localization of excitations. The analogue of the fractional charge state is also observed. Possible realizations of flat bands in a large class of metamaterials, including photonic crystals and electronic metamaterials, are discussed.
