  We use laser-cooled ion Coulomb crystals in the well-controlled environment
of a harmonic radiofrequency ion trap to investigate phase transitions and
defect formation. Topological defects in ion Coulomb crystals (kinks) have been
recently proposed for studies of nonlinear physics with solitons and as
carriers of quantum information. Defects form when a symmetry breaking phase
transition is crossed nonadiabatically. For a second order phase transition,
the Kibble-Zurek mechanism predicts that the formation of these defects follows
a power law scaling in the rate of the transition. We demonstrate a scaling of
defect density and describe kink dynamics and stability. We further discuss the
implementation of mass defects and electric fields as first steps toward
controlled kink preparation and manipulation.
