论文标题
石墨烯纳米荷尔等离激晶晶体波导中的山谷霍尔拓扑等离子体
Valley-Hall topological plasmons in a graphene nanohole plasmonic crystal waveguide
论文作者
论文摘要
我们证明，在由石墨烯纳米霍尔等离激元晶体制成的拓扑谷霍尔波导中可以实现Terahertz光波的单向和反向散射的免疫传播。为了对这些现象有更深入的洞察力，已经研究和优化了石墨烯纳米荷尔PLAMSONIC晶体的带图。我们发现，属于$ C_ {6V} $对称组具有Gapless Dirac锥体的石墨烯等离激元晶体，可以通过引入额外的纳米霍尔斯来掩盖该系统的对称点组，从而使该系统的对称点组从$ C_ {6V} $ C_ $ C_ c_ c_ {3v} $降低。利用此功能，我们通过将两个优化的石墨烯等离激元晶体放在一起，以构建打开的带隙内的Valley Polarley拓扑界面模式来设计一个镜子对称域壁界面界面。我们的计算分析表明，可以在极深的次波长尺度上实现山谷拓扑域壁壁界面模式，并且不依赖于外部静态磁场的应用。这项工作可能铺平了一种新的方式来开发高度累积的Terahertz等离子波导，以深波长度尺度。
We demonstrate that unidirectional and backscattering immune propagation of terahertz optical waves can be achieved in a topological valley-Hall waveguide made of graphene nanohole plasmonic crystals. In order to gain deeper physical insights into these phenomena, the band diagram of graphene nanohole plamsonic crystals has been investigated and optimized. We found that a graphene plasmonic crystal with nanohole arrays belonging to the $C_{6v}$ symmetry group possesses gapless Dirac cones, which can be gapped out by introducing extra nanoholes such that the symmetry point group of the system is reduced from $C_{6v}$ to $C_{3v}$. Taking advantage of this feature, we design a mirror symmetric domain-wall interface by placing together two optimized graphene plasmonic crystals so as to construct valley-polarized topological interface modes inside the opened bandgap. Our computational analysis shows that the valley-Hall topological domain-wall interface modes can be achieved at an extremely deep subwavelength scale, and do not rely on the application of external static magnetic fields. This work may pave a new way to develop highly-integrated and robust terahertz plasmonic waveguides at deep-subwavelength scale.
