Asymmetric transport in sonic valley Hall insulators

With the discovery of the quantum valley Hall insulators in sonic systems, the concept of valley degree of freedom in valleytronics of condensed physics has been introduced to sonic fields. Many papers concentrate on the transmission characteristics of the symmetric sonic topological valley states, which provide an equal splitting ratio at two ports; however, few studies focus on the transmission of the asymmetric sonic topological valley edge states. In this paper, we achieve asymmetric transport in a sonic valley Hall insulator, by introducing asymmetric edge states, thus we carry out waveguide with an arbitrary splitting ratio at the two ports. As an example, the sonic topological splitter with a splitting ratio of 1/2 at the ports is demonstrated in the simulation and experiment, and the robust transmission properties of this sonic splitter with defects are verified. This work has great potential for manipulating the distribution of sonic energy.