Two-Dimensional Melting of Colloidal Hard Spheres

Reentrant melting of two-dimensional colloidal systems

When a two-dimensional colloidal suspension of highly charged particles is subjected to a periodic one-dimensional (1D) light field, a liquid–solid transition can be induced. This phase transition is well known as light-induced freezing. However, upon further increase of the intensity, the crystal is found to remelt (laser-induced melting) to a 1D liquid. This reentrance behaviour is in good ag...

Anisotropic defect-mediated melting of two-dimensional colloidal crystals.

The melting transition of anisotropic two-dimensional (2D) crystals is studied in a model system of superparamagnetic colloids. The anisotropy of the induced dipole-dipole interaction is varied by tilting the external magnetic field off the normal to the particle plane. By analyzing the time-dependent Lindemann parameter as well as translational and orientational order we observe a 2D smecticli...

Melting of two-dimensional tunable-diameter colloidal crystals.

Melting of two-dimensional colloidal crystals is studied by video microscopy. The samples were composed of microgel spheres whose diameters could be temperature tuned, and whose pair potentials were measured to be short ranged and repulsive. We observed two-step melting from the crystal to a hexatic phase and from the hexatic to the liquid phase as a function of the temperature-tunable volume f...

Melting and spontaneous symmetry breaking in two-dimensional colloidal systems

Freezing of binary mixtures of colloidal hard spheres

The freezing phase transition in a binary suspension of conoidal hard spheres of diameter ratio a = 0.61 was studied by light scattering and scanning electron microscopy. The suspensions consisted of stericaHy stabilized poly( methyl methacrylate) spheres of diameters about 670 and 407 nm suspended in a near refractive indexed matched suspension medium composed of carbon disulphide and cis-deca...