Effective interactions and melting of a one-dimensional defect lattice within a two-dimensional confined colloidal solid.

We report Monte Carlo studies of a two-dimensional soft colloidal crystal confined in a strip geometry by parallel walls. The wall-particle interaction has corrugations along the length of the strip. Compressing the crystal by decreasing the distance between the walls induces a structural transition characterized by the sudden appearance of a one-dimensional array of extended defects each of which span several lattice parameters, a "soliton staircase." We obtain the effective interaction between the solitons. A Lindemann criterion shows that the reduction in dimensionality causes the finite soliton lattice to readily melt as the temperature is raised.