Dual-Band Helical Edge States and Discrete Dirac Vortices in Solid-State Elastic Waves

Dual-band equipment has unique advantages as regards ensuring the stability of wireless commu-nication and improving efficiency. With the development of topological photonics and phononics, electromagnetic and mechanical wave transmission with simultaneous advantages, e.g., antireflection, broadband, and nondispersion characteristics, has been simultaneously realized. This outcome has greatly improved elastic wave manipulation performance in solids, which are important media for wireless com-munication. Here, using a plate phononic crystal (PnC), a dual-mode elastic topological insulator is theoretically designed and experimentally realized, and the quantum spin Hall effect is observed under a dual band. Using discrete Kekule modulation to construct the PnC multidomain junction, dual-mode and dual-band Dirac vortexes, i.e., a type of topological corner state, are obtained in a single PnC. These trans-mitted and localized topological states have the same excellent properties as their antecedents, which are obtained with single-band materials. The implementation mechanisms are diverse and applicable to multi-ple modes and broad frequencies, offering antijamming, low-loss, high-efficiency, and high-capacity signal processing components. The findings of this study will aid development of solid-state topology PnCs, as well as future topological-phononic integrated circuits with high performance and multifunctionality.

Automated summary

Dual-band equipment has unique advantages in ensuring wireless communication stability and improving efficiency. In this study, a dual-mode elastic topological insulator is designed and experimentally realized, and the quantum spin Hall effect is observed under dual bands. By constructing a multidomain junction, dual-mode and dual-band Dirac vortexes are obtained in a single structure, offering excellent performance. These findings contribute to the development of solid-state topological-phononic integrated circuits with high performance and multifunctionality.