Tailoring of phononic band structures in colloidal crystals

TL;DR

This study experimentally demonstrates how the phononic band structure of 2D colloidal crystals can be tuned using light-induced substrate potentials, aligning with theoretical predictions and suggesting new methods for designing tunable phononic materials.

Contribution

It provides experimental validation of phononic band tuning in colloidal crystals and proposes external field control as a novel approach for phononic crystal fabrication.

Findings

Phonon band structures can be tuned by substrate potential symmetry and depth.

Binary crystal calculations suggest pair potential variations also enable band engineering.

External fields can be used to create tunable phononic band gaps.

Abstract

We report an experimental study of the elastic properties of a two-dimensional (2D) colloidal crystal subjected to light-induced substrate potentials. In agreement with recent theoretical predictions [H.H. von Gruenberg and J. Baumgartl, Phys. Rev. E 75, 051406 (2007)] the phonon band structure of such systems can be tuned depending on the symmetry and depth of the substrate potential. Calculations with binary crystals suggest that phononic band engineering can be also performed by variations of the pair potential and thus opens novel perspectives for the fabrication of phononic crystals with band gaps tunable by external fields.