Manipulation and Characterization of the Valley-Polarized Topological Kink States in Graphene-Based Interferometers

Valley polarized topological kink states, existing broadly in the domain wall of hexagonal lattice systems, are identified in experiments. Using an Aharanov-Bohm interferometer composed of domain walls in graphene systems, we study the periodical modulation of a pure valley current in a large range by tuning the magnetic field or the Fermi level. For a monolayer graphene device, there exists one topological kink state, and the oscillation of the transmission coefficients has a single period. The π Berry phase and the linear dispersion relation of kink states can be extracted from the transmission data. For a bilayer graphene device, there are two topological kink states with two oscillation periods. Our proposal provides an experimentally feasible route to manipulate and characterize the valley-polarized topological kink states in classical wave and electronic graphene-type crystalline systems. The realization of the proposal in photonic graphene is also discussed.

This work is financially supported by NSFC under Grant No. 11874298 and NSF of Jiangsu Province, China under Grant No BK20160007.