Crystal growth as an excitable medium

TL;DR

This paper shows that crystal growth patterns like spirals and targets can be understood as excitable media, linking physical crystal growth phenomena with biological and chemical systems, and offering new insights into their underlying physics.

Contribution

It establishes a formal framework connecting crystal growth patterns with excitable media, extending the concept beyond traditional solid crystals to biological materials like nacre.

Findings

Crystal growth patterns can be modeled as excitable media.

The framework applies to biological materials such as nacre.

Understanding this link may facilitate cross-disciplinary insights.

Abstract

Crystal growth has been widely studied for many years, and, since the pioneering work of Burton, Cabrera and Frank, spirals and target patterns on the crystal surface have been understood as forms of tangential crystal growth mediated by defects and by two-dimensional nucleation. Similar spirals and target patterns are ubiquitous in physical systems describable as excitable media. Here, we demonstrate that this is not merely a superficial resemblance, that the physics of crystal growth can be set within the framework of an excitable medium, and that appreciating this correspondence may prove useful to both fields. Apart from solid crystals, we discuss how our model applies to the biomaterial nacre, formed by layer growth of a biological liquid crystal.