Anisotropic Hypersonic Phonon Propagation in Films of Aligned Ellipsoids

作者:Beltramo Peter J*; Schneider Dirk; Fytas George; Furst Eric M
来源:Physical Review Letters, 2014, 113(20): 205503.
DOI:10.1103/PhysRevLett.113.205503

摘要

A material with anisotropic elastic mechanical properties and a direction-dependent hypersonic band gap is fabricated using ac electric field-directed convective self-assembly of colloidal ellipsoids. The frequency of the gap, which is detected in the direction perpendicular to particle alignment and entirely absent parallel to alignment, and the effective sound velocities can be tuned by the particle aspect ratio. We hypothesize that the band gap originates from the primary eigenmode peak, the m-splitted ( s, 1,2) mode, of the particle resonating with the effective medium. These results reveal the potential for powerful control of the hypersonic phononic band diagram by combining anisotropic particles and self-assembly.

  • 出版日期2014-11-14