Defect-induced solitons in double Peierls chain model

The generation and manipulation of topological solitons are of great importance in fundamental and practical aspects. Recently, chiral solitons and their topological operations have been experimentally discovered in the double Peierls chains of an indium atomic wire on a silicon substrate. Here, we theoretically study the role of defects at edges as generators of topological chiral solitons in the double Peierls chain model composed of two Su–Schrieffer–Heeger chains with interchain coupling. We classify four types of defects according to the combination of strong or weak defects in each chain. Two strong defects at an edge remain stable and do not generate a soliton. Interestingly, two weak defects at an edge generate a non-chiral soliton, while a weak defect in a chain and a strong defect in the other generate either a right-chiral or left-chiral soliton. Our work opens a pathway to generate and manipulate topological solitons in various one-dimensional systems.