Phonon dispersion in hypersonic two-dimensional phononic crystal membranes

We investigate experimentally and theoretically the acoustic phonon propagation in two-dimensional phononic crystal membranes. Solid-air and solid-solid phononic crystals were made of square lattices of holes and Au pillars in and on 250 nm thick single crystalline Si membrane, respectively. The hyp...

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Bibliographic Details
Published in:Physical review. B, Condensed matter and materials physics Condensed matter and materials physics, 2015-02, Vol.91 (7)
Main Authors: Graczykowski, B, Sledzinska, M, Alzina, F, Gomis-Bresco, J, Reparaz, J S, Wagner, M R, Torres, C M Sotomayor
Format: Article
Language:English
Subjects:
Condensed matter
Crystals
Dispersions
Hypersonic flow
Mathematical models
Membranes
Phonons
Pillars
Two dimensional
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Summary:We investigate experimentally and theoretically the acoustic phonon propagation in two-dimensional phononic crystal membranes. Solid-air and solid-solid phononic crystals were made of square lattices of holes and Au pillars in and on 250 nm thick single crystalline Si membrane, respectively. The hypersonic phonon dispersion was investigated using Brillouin light scattering. Volume reduction (holes) or mass loading (pillars) accompanied with second-order periodicity and local resonances are shown to significantly modify the propagation of thermally activated GHz phonons. We use numerical modeling based on the finite element method to analyze the experimental results and determine polarization, symmetry, or three-dimensional localization of observed modes.
ISSN:1098-0121
1550-235X
DOI:10.1103/PhysRevB.91.075414