Still Life – Fast Moving: A kinetic view of crystal growth

Abstract

Classical Nucleation Theory is dead. For over a century, it has been the lens through which scientists have considered the birth of crystals. As with many theories though, it existed to describe a process that was unobservable, the atomic and molecular interactions occurring at Angstrom length scales hidden from view, necessitated a mathematical framework on which to hang our observations. Recently however, the design of crystal growth experiments far from equilibrium and the rise of high-resolution imaging has brought this realm into sharper focus and we can now see into a world that Classical Nucleation Theory cannot describe. This article does not serve as a postmortem for Classical Nucleation Theory, instead it highlights the new crystal growth paradigms that are taking its place in our understanding of crystal formation. These paradigms invariably embrace the kinetic, rather than the thermodynamic and so whilst the existing theories hold (reasonably) true for some crystal growth processes performed with low growth rates and therefore close to thermodynamic equilibrium, these new experimental innovations in crystal growth are using kinetic control to direct and affect growth that is far beyond what traditional theory can describe.