人工石墨烯结构中有带隙的拓扑界面态和拓扑角态

Gapped topological kink states and topological corner states in honeycomb lattice

近年来,六角晶格体系中子格破缺畴壁或31/2×31/2晶格畸变畴壁导致的无能隙的拓扑界面态分别引起了广泛的关注.本文通过理论分析结合光子晶体实验研究了同时存在以上两种机制时六角人工石墨烯体系畴壁导致的拓扑态.研究发现子格破缺畴壁和31/2×31/2畴壁独立引起的无能隙的拓扑界面态有类似的拓扑起源;然而由于质量正交,在两种机制共存时,畴壁存在有能隙的拓扑界面态.当两类畴壁交叉时,在交叉点存在拓扑角态,这为二阶拓扑绝缘体研究提供了一个新的视角.进一步,发现通过调控这两类畴壁,可以在一个样品有效集成多种拓扑态并调控它们的相互作用.基于此,提出将无能隙/有能隙拓扑界面态以及拓扑角态集成到同一光子晶体样品,从而构成拓扑量子点的新设想.本文的主要结果不依赖于具体的实验平台,在凝聚态体系和其他经典波体系也成立.

Based on the tight-binding calculations on honeycomb lattice and photonic experimental visualization on artificial graphene(AG), we report the domain-wall-induced gapped topological kink states and topological corner states. In honeycomb lattice, domain walls(DWs) with gapless topological kink states could be induced either by sublattice symmetry breaking or by lattice deformation. We find that the coexistence of these two mechanisms will induce DWs with gapped topological kink states. Significantly, the intersection of these two types of DWs gives rise to topological corner state localized at the crossing point.Through the manipulation of the DWs, we show AG with honeycomb lattice structure not only a versatile platform supporting multiple topological corner modes in a controlled manner, but also possessing promising applications such as fabricating topological quantum dots composed of gapped topological kink states and topological corner states.