Frequency-dependent surface wave suppression at the Dirac point of an acoustic graphene analog
| Autor: | Nicholas Gangemi, Caleb F. Sieck, Joseph Vignola, Diego Turo, Alec K. Ikei, Amelia Vignola, Jeffrey Baldwin, Steven Liskey, Aaron Edmunds, William Wilson, Michael Boone, Gregory Yesner, Douglas Photiadis, Bernard Matis |
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| Rok vydání: | 2023 |
| Předmět: | |
| Zdroj: | The Journal of the Acoustical Society of America. 153:A362-A362 |
| ISSN: | 1520-8524 0001-4966 |
| DOI: | 10.1121/10.0019168 |
| Popis: | The dispersion of bound acoustic surface waves over hexagonal lattices of resonant cavities has been shown to be analogous to the dispersion of charge transport in carbon graphene. Of particular interest is the frequency range close to the acoustic Dirac point where novel physics is predicted to occur. In this study, we measure the dispersion curves of a single-layer acoustic graphene analogue with high resolution one-dimensional spatial scansand show how the curves can be suppressed (near and at the Dirac point) by strong variations in the impedance boundary conditions between the free field and surface wave regimes under certain experimental conditions. By systematically varying these impedance boundary conditions using different surface wave excitation techniques, we demonstrate that increased Rayleigh scattering and diffractive excitation can increase the dispersed surface wave pressure amplitude to an extent that the impedance-based wave suppression is circumvented. The improved conditions for observing acoustic Dirac points for two samples with two distinct operational frequency ranges are reported. The single-layer acoustic graphene analogue results discussed here are important for advancing the field of acoustic twistronics. |
| Databáze: | OpenAIRE |
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