Engineering the hypersonic phononic band gap of Hybrid Bragg Stacks

Schneider, D., Liaqat, F., El Boudouti, E. H., El Hassouani, Y., Djafari-Rouhani, B., Tremel, W., Butt, H.-J. and Fytas, G. (2012) Engineering the hypersonic phononic band gap of Hybrid Bragg Stacks. Nano Letters, 12(6), pp. 3101-3108. (doi: 10.1021/nl300982d)

Abstract

We report on the full control of phononic band diagrams for periodic stacks of alternating layers of poly(methyl methacrylate) and porous silica combining Brillouin light scattering spectroscopy and theoretical calculations. These structures exhibit large and robust on-axis band gaps determined by the longitudinal sound velocities, densities, and spacing ratio. A facile tuning of the gap width is realized at oblique incidence utilizing the vector nature of the elastic wave propagation. Off-axis propagation involves sagittal waves in the individual layers, allowing access to shear moduli at nanoscale. The full theoretical description discerns the most important features of the hypersonic one-dimensional crystals forward to a detailed understanding, a precondition to engineer dispersion relations in such structures.

• Item Type: Articles
• Keywords: Phononics; band gap; superlattices; hypersound propagation; Brillouin spectroscopy
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Liaqat, Dr Faroha
• Authors: Schneider, D., Liaqat, F., El Boudouti, E. H., El Hassouani, Y., Djafari-Rouhani, B., Tremel, W., Butt, H.-J., and Fytas, G.
• College/School: College of Science and Engineering > School of Engineering > Biomedical Engineering
• Journal Name: Nano Letters
• Publisher: American Chemical Society
• ISSN: 1530-6984
• ISSN (Online): 1530-6992
• Copyright Holders: American Chemical Society