Institute of Theoretical and Applied Physics, School of Physical Science and Technology and Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou, China.
School of Physics and Optoelectronics, South China University of Technology, Guangzhou, China.
Nat Mater. 2022 Apr;21(4):430-437. doi: 10.1038/s41563-022-01200-w. Epub 2022 Mar 21.
Gauge fields play a major role in understanding quantum effects. For example, gauge flux insertion into single unit cells is crucial towards detecting quantum phases and controlling quantum dynamics and classical waves. However, the potential of gauge fields in topological materials studies has not been fully exploited. Here, we experimentally demonstrate artificial gauge flux insertion into a single plaquette of a sonic crystal with a gauge phase ranging from 0 to 2π. We insert the gauge flux through a three-step process of dimensional extension, engineering a screw dislocation and dimensional reduction. Additionally, the single-plaquette gauge flux leads to cyclic spectral flows across multiple bandgaps that manifest as topological boundary states on the plaquette and emerge only when the flux-carrying plaquette encloses the Wannier centres. We termed this phenomenon as the topological Wannier cycle. This work paves the way towards sub-unit-cell gauge flux, enabling future studies on synthetic gauge fields and topological materials.
规范场在理解量子效应方面起着重要作用。例如，规范通量插入单个单元胞对于探测量子相、控制量子动力学和经典波至关重要。然而，规范场在拓扑材料研究中的潜力尚未得到充分利用。在这里，我们通过扩展维度、工程螺位错和降维的三步过程，实验演示了将人工规范通量插入到声子晶体的单个 plaquette 中，规范相位范围从 0 到 2π。此外，单个 plaquette 规范通量导致多个带隙中的循环能带流，这些能带流表现为 plaquette 上的拓扑边界态，只有当承载通量的 plaquette 包围 Wannier 中心时才会出现。我们将这种现象称为拓扑 Wannier 循环。这项工作为亚单元胞规范通量铺平了道路，为未来的合成规范场和拓扑材料研究奠定了基础。
