Topological end states in one-dimensional Su–Schrieffer–Heeger-like chain electric circuits

Abstract

Topological circuits provide a convenient experimental platform for observing topological states. In this work, we construct a one-dimensional Su-Schrieffer-Heeger(SSH)-like chain in topological electric circuits and find two types of end states, but only the type-II end states are pinned at zero admittance. The topological properties can be characterized by the sum of Zak phases, which related to the ratio of inter-cell capacitors to intra-cell capacitors. Theoretical and experimental results, which agree well with each other, of these two end states are well demonstrated by impedance peaks. We examine the robustness of these two end states by adding extra capacitors. Our work enriches the study of topological circuits and provides an example for investigating the exotic topological physics.