Multiple-scale structures: from Faraday waves to soft-matter quasicrystals

TL;DR

This paper explores the formation and stability of soft-matter quasicrystals with multiple-scale structures, using models based on Faraday wave patterns, and predicts new stable quasicrystalline symmetries for potential experimental observation.

Contribution

It extends and refines a two-decade-old model linking Faraday waves to soft-matter quasicrystals, providing new analytical methods and stability predictions for complex symmetries.

Findings

Predicted new stable quasicrystalline structures with octagonal and higher symmetries.

Corrected discrepancies in earlier models and expanded analytical approaches.

Suggested potential for experimental observation of these novel structures.

Abstract

For many years, quasicrystals were observed only as solid-state metallic alloys, yet current research is now actively exploring their formation in a variety of soft materials, including systems of macromolecules, nanoparticles and colloids. Much effort is being invested in understanding the thermodynamic properties of these soft-matter quasicrystals in order to predict and possibly control the structures that form, and hopefully to shed light on the broader yet unresolved general questions of quasicrystal formation and stability. Moreover, the ability to control the self-assembly of soft quasicrystals may contribute to the development of novel photonic or other applications based on self-assembled metamaterials. Here a path is followed, leading to quantitative stability predictions, that starts with a model developed two decades ago to treat the formation of multiple-scale quasiperiodic Faraday waves (standing wave patterns in vibrated fluid surfaces) and which was later mapped onto systems of soft particles, interacting via multiple-scale pair potentials. The article reviews, and substantially expands, the quantitative predictions of these models, while correcting a few discrepancies in earlier calculations, and presents new analytical methods for treating the models. In so doing, a number of new stable quasicrystalline structures with octagonal, octadecagonal and higher-order symmetries, some of which may, it is hoped, be observed in future experiments.