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

TL;DR

This paper demonstrates how to manipulate and characterize valley polarized topological kink states in graphene using an Aharanov-Bohm interferometer, revealing their properties through transmission oscillations.

Contribution

It introduces an experimental method to control and analyze valley polarized kink states in graphene-based systems via magnetic field and Fermi level tuning.

Findings

Single oscillation period for monolayer graphene kink state.

Extraction of Berry phase and linear dispersion from transmission data.

Two oscillation periods observed for bilayer graphene kink states.

Abstract

Valley polarized topological kink states, existing broadly in the domain wall of hexagonal lattices systems, are identified in experiments, unfortunately, only very limited physical properties being given. Using an Aharanov-Bohm interferometer composed of domain walls in graphene systems, we study the periodical modulation of pure valley current in a large range by tuning the magnetic field or the Fermi level. For monolayer graphene device, there exists one topological kink state, and the oscillation of transmission coefficients have single period. The $\pi$ Berry phase and the linear dispersion relation of kink states can be extracted from the transmission data. For bilayer graphene device, there are two topological kink states with two oscillation periods. Our proposal provides an experimental feasible route to manipulate and characterize the valley polarized topological kink states in classical wave and electronic graphene-type crystalline systems.