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.