Defect nucleation in quenched freely suspended smectic liquid crystal films

Freely suspended films of smectic liquid crystals, which can be as thin as two molecular layers, are a natural choice for studying ordering and phase transitions in 2D. One 2D system of ongoing interest is that of the XY-model, which describes the U(1) symmetry group of rotations, broken by either a complex number or 2D vector. The XY-model gives rise to topological defects, or vortices, with interesting implications for phase transitions in two dimensions eg. Kosterlitz-Thouless transitions. Here, we describe our recent experiments focusing on the nucleation of topological defects in the quasi-2D system of freely-suspended smectic films. By rapidly quenching a film (inducing a rapid phase transition from an ordered to a disordered phase), and studying the evolution of the dynamics with a high-speed video camera, we are able to visualize defect nucleation in smectic C (tilted) films, and we will discuss the role that islands (pancake-like, circular regions with additional smectic layers bounded by an edge dislocation) play in mediating the creation of these defects.