Topological Phononic Crystals with One-Way Elastic Edge Waves

We report a new type of phononic crystals with topologically nontrivial band gaps 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 (anomalous) Hall effect. We investigate the response of both hexagonal and square gyroscopic lattices and observe bulk Chern numbers of 1 and 2, indicating that these structures support single and multimode edge elastic waves immune to backscattering. These robust one-way phononic waveguides could potentially lead to the design of a novel class of surface wave devices that are widely…

• NS
  National Science Foundation

  Awards: CMMI-1120724, DMR-1419807, CMMI-1149456
• UD
  U.S. Department of Energy

  Award: DE-SC0001299
• HS
  Harvard School of Engineering and Applied Sciences
• MR
  Materials Research Science and Engineering Center, Harvard University

  Award: DMR-1420570
• KI
  Kavli Institute for Theoretical Physics, University of California, Santa Barbara