Realization of higher-order topology in bilayer asymmetric Su–Schrieffer–Heeger topological electric circuits
Shengqun Guo, Jinke Huang, Ruimin Huang, Fengjiang Zhuang, Shaojian Su, Zhili Lin, Weibin Qiu, Jianchao Su, Xin Wang
Abstract
In this Letter, we report on the realization of higher-order topology in electric circuit systems by generalizing the two-dimensional asymmetric Su–Schrieffer–Heeger (SSH) model to a bilayer model, which consists of two monolayer models that are directly coupled. Such a system inherits the topological properties of its monolayer counterparts and exhibits the existence of split edge states and corner states in a finite size. As well, the number of topological states is doubled due to the mirror-stacking operation. This work substantiates the existence of rich topological states in bilayer asymmetric SSH electric circuits and may inspire further research into higher-order topological insulators in artificial topological systems.