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 agreement with predictions based on Monte Carlo simulations. We suggest explaining this intriguing phenomenon in terms of particle fluctuations which tend to stabilize the crystalline phase.