Crystallization in Sedimentation Profiles of Hard Spheres

Equilibrium density profiles of a hard-sphere suspension in a gravitational field are calculated using Monte Carlo simulations. For increasing gravity there is a discontinuous freezing transition induced by the container wall where few crystalline layers are spontaneously formed at the bottom of the sample. This crystalline part then grows continuously as the gravitational field is further enhanced. The results are compared with density functional theory of freezing where a weighted density approximation is used. While good overall agreement of the laterally averaged profile and the lateral crystallinity is achieved, density functional theory yields a discontinuous crystal growth via layering transitions.