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arXiv 1809.07565physics.opticscond-mat.mes-hallcond-mat.othernlin.PS
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极化激元拓扑绝缘体的共振边态开关

Resonant edge-state switching in polariton topological insulators

Yiqi Zhang, Yaroslav V. Kartashov, Yanpeng Zhang, Lluis Torner, Dmitry V. Skryabin

摘要:

拓扑绝缘体是在其界面处支持单向边缘态的独特器件。由于拓扑保护,这样的边缘状态在存在无序的情况下持续存在,并且在与缺陷相互作用时不经历反向散射。我们表明,尽管拓扑保护和这样的状态在相对的边缘的一个带进行相反的电流的事实,存在一种物理机制,允许共振耦合拓扑激发传播在相对的边缘。这种机制利用系统参数的弱周期性时间调制,并且不影响系统的内部对称性和拓扑结构。我们研究这种机制在截断蜂窝阵列的微腔柱,拓扑绝缘是可能的极化激元下的自旋轨道耦合和塞曼分裂在外部磁场的共同作用。电势的时间调制导致具有相同布洛赫动量但位于相对边缘的拓扑状态之间的周期性切换。开关率被发现增加较窄的带状结构和较大的调制深度,但它是非单调变化的输入边缘状态的布洛赫动量。我们的研究结果提供了一个很有前途的实现耦合器件的拓扑保护状态的基础上。所提出的方案可以用于其他拓扑光子和凝聚态系统,包括Floquet绝缘体和石墨烯。

英文摘要:

Topological insulators are unique devices supporting unidirectional edge states at their interfaces. Due to topological protection, such edge states persist in the presence of disorder and do not experience backscattering upon interaction with defects. We show that despite the topological protection and the fact that such states at the opposite edges of a ribbon carry opposite currents, there exists a physical mechanism allowing to resonantly couple topological excitations propagating at opposite edges. Such mechanism uses weak periodic temporal modulations of the system parameters and does not affect the internal symmetry and topology of the system. We study this mechanism in truncated honeycomb arrays of microcavity pillars, where topological insulation is possible for polaritons under the combined action of spin-orbit coupling and Zeeman splitting in the external magnetic field. The temporal modulation of the potential leads to a periodic switching between topological states with the same Bloch momentum, but located at the opposite edges. The switching rate is found to increase for narrower ribbon structures and for larger modulation depth, though it is changing nonmonotonically with the Bloch momentum of the input edge state. Our results provide a promising realization of a coupling device based on topologically protected states. The proposed scheme can be used in other topological photonic and condensed matter systems, including Floquet insulators and graphene.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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