Acoustic spin-Chern insulator induced by synthetic spin-orbit coupling with spin conservation breaking
Acoustic spin-Chern insulator induced by synthetic spin-orbit coupling with spin conservation breaking
复制标题
由具有自旋守恒破缺的合成自旋轨道耦合引起的声自旋陈绝缘体
DOI：
10.1038/s41467-020-17039-1
复制
发表时间：
2020-06-26
影响因子：
16.6
通讯作者：
Liu, Zhengyou
中科院分区：
文献类型：
--
作者：
Deng, Weiyin;Huang, Xueqin;Liu, Zhengyou
经典波的拓扑保护表面模式有望实现从能量的鲁棒传输到可靠的信息处理网络的各种应用。然而，实现量子霍尔效应的模拟以及量子自旋霍尔效应的途径分别被磁场的要求或费米量子统计的存在阻碍了声学。在这里，我们构建了一个二维拓扑声学晶体诱导的合成自旋轨道耦合，拓扑绝缘体的一个重要组成部分，自旋不守恒。我们的设置使我们能够摆脱对称性的限制，因为我们依赖于一个非零的“自旋”陈数的概念。我们实验表征新兴的边界状态，我们显示是无隙和螺旋。更重要的是，我们在H型器件中观察到了自旋翻转输运，明显地证明了边界态的自旋不守恒。在声学系统中，量子自旋霍尔物理很少被观察到，因为缺少关键的自旋轨道耦合。在这里，作者构建了一个合成的自旋-轨道耦合声学晶体，并观察了无带隙螺旋边界态和自旋翻转效应。
Topologically protected surface modes of classical waves hold the promise to enable a variety of applications ranging from robust transport of energy to reliable information processing networks. However, both the route of implementing an analogue of the quantum Hall effect as well as the quantum spin Hall effect are obstructed for acoustics by the requirement of a magnetic field, or the presence of fermionic quantum statistics, respectively. Here, we construct a two-dimensional topological acoustic crystal induced by the synthetic spin-orbit coupling, a crucial ingredient of topological insulators, with spin non-conservation. Our setup allows us to free ourselves of symmetry constraints as we rely on the concept of a non-vanishing "spin" Chern number. We experimentally characterize the emerging boundary states which we show to be gapless and helical. More importantly, we observe the spin flipping transport in an H-shaped device, demonstrating evidently the spin non-conservation of the boundary states. In acoustic systems, quantum spin Hall physics is rarely observed because the crucial ingredient spin-orbit coupling is missing. Here, the authors construct an acoustic crystal with synthetic spin-orbit coupling and observe gapless helical boundary states as well as spin flipping effect.