We report a new type of phononic crystals with topologically non-trivial bandgaps for both longitudinal and transverse polarizations, resulting in protected one-way elastic edge waves. In our design, gyroscopic inertial effects are used to break the time-reversal symmetry and realize the phononic analogue of the electronic quantum Hall effect. We investigate the response of both hexagonal and square gyroscopic lattices and observe bulk Chern number of 1 and 2, indicating that these structures support single and multi-mode edge elastic waves immune to back-scattering. These robust one-way phononic waveguides could potentially lead to the design of a novel class of surface wave devices that are widely used in electronics, telecommunication and acoustic imaging.
@article{arxiv.1504.01374,
title = {Topological Phononic Crystals with One-Way Elastic Edge Waves},
author = {Pai Wang and Ling Lu and Katia Bertoldi},
journal= {arXiv preprint arXiv:1504.01374},
year = {2015}
}