Localized states induced by uniaxial strain in graphene quantum dots

Abstract

The construction of localized states has been one of the hot research topics in recent years. In this paper, an effective method of constructing the localized states (corner state, edge state and domain wall state) in graphene quantum dots is proposed theoretically by using the uniaxial strain effect. The research shows that the distribution characteristics and forms of these localized states are closely related to the uniaxial strain direction. Specifically, the formation of these localized states is mainly attributed to the inconsistent hopping amplitude caused by the uniaxial strain, which makes graphene quantum dots become an extended 2D Su-Schrieffer-Heeger (SSH) model. It must be emphasized that the formation of these local states only requires the effect of strain, and all of them are in the band gap of the system, so they are very easy to be directly observed and used as single-channel quantum wires. Then, we propose a method to analyze the localized states by building a two-dimensional extended SSH model through a one-dimensional SSH chain. The theoretical speculation of our proposed method is highly consistent with the simulated local states phenomenon induced by uniaxial strain applied to the monolayer graphene. This method of constructing the localized states by using uniaxial strain to realize the extended two-dimensional SSH model is not only suitable for electronic crystals like graphene, but also for artificial crystals like photonic crystals and acoustic crystals. Our findings provide a new ideas for circuit design for quantum computing.