Plasmons can be supported on graphene sheets as the Dirac electrons oscillate collectively. A tight-binding model for graphene plasmons is a good description as the field confinement in the normal direction is strong. With this model, the topological properties of plasmonic bands in multilayer graphene systems are investigated. The Zak phases of periodic graphene sheet arrays are obtained for different configurations. Analogous to Su-Schrieffer-Heeger (SSH) model in electronic systems, topological edge plasmon modes emerge when two periodic graphene sheet arrays with different Zak phases are connected. Interestingly, the dispersion of these topological edge modes is the same as that in the monolayer graphene and is invariant as the geometric parameters of the structure such as the separation and period change. These plasmonic edge states in multilayer graphene systems can be further tuned by electrical gating or chemical doping. © 2015 Optical Society of America.
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledgements: This work is supported the National Natural Science Foundation of China (Grant No. 11304038) and the Fundamental Research Funds for the Central Universities (Grant No. CQDXWL-2014-Z005). Work in Hong Kong is supported by Hong Kong Research Grant Council AOE/P-02/12.