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Published May 18, 2018 | Published + Supplemental Material + Submitted
Journal Article Open

Spiral-Based Phononic Plates: From Wave Beaming to Topological Insulators


Phononic crystals and metamaterials can sculpt elastic waves, controlling their dispersion using different mechanisms. These mechanisms are mostly Bragg scattering, local resonances, and inertial amplification, derived from ad hoc, often problem-specific geometries of the materials' building blocks. Here, we present a platform that ultilizes a lattice of spiraling unit cells to create phononic materials encompassing Bragg scattering, local resonances, and inertial amplification. We present two examples of phononic materials that can control waves with wavelengths much larger than the lattice's periodicity. (1) A wave beaming plate, which can beam waves at arbitrary angles, independent of the lattice vectors. We show that the beaming trajectory can be continuously tuned, by varying the driving frequency or the spirals' orientation. (2) A topological insulator plate, which derives its properties from a resonance-based Dirac cone below the Bragg limit of the structured lattice of spirals.

Additional Information

© 2018 American Physical Society. Received 21 November 2017; published 15 May 2018. The authors thank the reviewers for their helpful comments and A. Palermo for his support in the implementation of the complex eigenvalue computations. This work was supported by ETH Postdoctoral Fellowship FEL-26 15-2 to O. R. B. and ETH Grant No. ETH-24 15-2. A. F. and O. R. B. contributed equally to this work.

Attached Files

Published - PhysRevLett.120.205501.pdf

Submitted - 1712.01360.pdf

Supplemental Material - Spirals_ParameterAnim.mp4

Supplemental Material - Supp_PRL.pdf


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August 19, 2023
October 18, 2023