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, topological properties of plasmonic bands in multilayer graphene systems are investigated. The Zak phases for periodical graphene arrays are discussed in 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 geometric parameters of the structures such as the separation and period changes. These plasmonic edge states can be further demonstrated in microwave regime by employing spoof surface plasmons.
About the speaker
Prof Dezhuan Han received his MS from New York University and PhD from Fudan University. He then did his postdoctoral studies at the Hong Kong University of Science and Technology. Since 2013, he has been appointed as Assistant Professor of Applied Physics at Chongqing University under the Young Talent Scheme.
Prof Han’s research interests include micro- and nano- photonic structures and geometric phases in electromagnetic systems.
The seminar is free and open to all. Seating is on a first-come, first-served basis.
