Melting transition in a quasi-two-dimensional colloid suspension: Influence of the colloid-colloid interaction

We report the results of a study, using digital video microscopy, of the me lting transition in a quasi-two-dimensional suspension of uncharged silica spheres. This system was chosen to further test the dependence of the two-d imensional melting transition on the functional form of the colloid-colloid interaction. Our experimental data show that the solid phase undergoes a f irst order transition directly to the liquid phase. The system studied yiel ds no evidence of the existence of a hexatic phase interpolating between th e solid and liquid phases in the melting Process.