Plasmon Reflections by Topological Electronic Boundaries in Bilayer Graphene
Plasmon Reflections by Topological Electronic Boundaries in Bilayer Graphene
复制标题
DOI：
10.1021/acs.nanolett.7b03816
复制
发表时间：
2017-11-01
期刊：
影响因子：
10.8
通讯作者：
Fogler, Michael M.
中科院分区：
文献类型：
--
作者：
Jiang, Bor-Yuan;Ni, Guang-Xin;Fogler, Michael M.
在双层石墨烯中分隔AB和BA层间堆叠区域的畴壁作为结构孤子、拓扑电子边界和纳米级等离子体散射体的新例子引起了人们的注意。我们表明，强耦合域壁的红外纳米成像实验中观察到的表面等离子体是由于拓扑手性模式局限于墙壁。这些手征模之间的光学跃迁和带连续增强了局域电导率，这导致了畴壁的等离子体反射。成像揭示了两种等离子体驻波干涉图案，我们归因于剪切和拉伸畴壁。我们计算的电子结构的两个壁品种，并表明，拉伸壁包含额外的限制带产生的局部导电性的结构特定的对比度，与实验一致。在这项工作中揭示的约束模式和表面等离子体激元散射之间的耦合，预计是常见的其他拓扑电子边界中发现的货车德瓦尔斯材料。这种耦合提供了一个定性的新途径控制纳米结构中的等离子体。
Domain walls separating regions of AB and BA interlayer stacking in bilayer graphene have attracted attention as novel examples of structural solitons, topological electronic boundaries, and nanoscale plasmonic scatterers. We show that strong coupling of domain walls to surface plasmons observed in infrared nanoimaging experiments is due to topological chiral modes confined to the walls. The optical transitions among these chiral modes and the band continua enhance the local conductivity, which leads to plasmon reflection by the domain walls. The imaging reveals two kinds of plasmonic standing-wave interference patterns, which we attribute to shear and tensile domain walls. We compute the electronic structure of both wall varieties and show that the tensile wall contains additional confined bands which produce a structure-specific contrast of the local conductivity, in agreement with the experiment. The coupling between the confined modes and the surface plasmon scattering unveiled in this work is expected to be common to other topological electronic boundaries found in van der Waals materials. This coupling provides a qualitatively new pathway toward controlling plasmons in nanostructures.