论文标题
二维弱拓扑绝缘子的实验实现
Experimental realization of two-dimensional weak topological insulators
论文作者
论文摘要
我们报告了具有奇迹时间和手性对称性的无旋su-schrieffer-heeger回路中二维（2D）弱拓扑绝缘子（WTI）的实验实现。强大而弱的$ \ MATHBB {Z} _2 $拓扑索引被用来解释实验发现，即当我们调节中心对称电路变形时，DIRAC半学相（DSM）相和四个WTI阶段依次出现。在DSM相中，发现Dirac锥体是高度各向异性的，并且不会固定在任何高对称点上，但可以在Brillouin区域中广泛移动，最终导致WTIS之间的相变。此外，我们通过设计空间不均匀的节点连接来观察一对平流域壁状态。我们的工作为2D WTI提供了第一个实验证据，这显着提高了我们对拓扑绝缘体的强大和弱性，平坦带的稳健性以及dirac锥体的巡回和各向异性特征的理解。
We report the experimental realization of two-dimensional (2D) weak topological insulator (WTI) in spinless Su-Schrieffer-Heeger circuits with parity-time and chiral symmetries. Strong and weak $\mathbb{Z}_2$ topological indexes are adopted to explain the experimental findings that a Dirac semimetal (DSM) phase and four WTI phases emerge in turn when we modulate the centrosymmetric circuit deformations. In DSM phase, it is found that the Dirac cone is highly anisotropic and not pinned to any high-symmetry points but can widely move within the Brillouin zone, which eventually leads to the phase transition between WTIs. In addition, we observe a pair of flat-band domain wall states by designing spatially inhomogeneous node connections. Our work provides the first experimental evidence for 2D WTIs, which significantly advances our understanding on the strong and weak nature of topological insulators, the robustness of flat bands, and the itinerant and anisotropic feature of Dirac cones.
