Effect of Fluctuations on the Freezing of a Colloidal Suspension in an External Periodic Potential

TL;DR

This paper investigates how fluctuations influence the freezing transition of colloidal suspensions under external periodic potentials, revealing that fluctuations can stabilize the liquid phase and alter the transition's nature.

Contribution

It extends density functional theory to include fluctuations, showing they preserve the continuous transition and stabilize the liquid at high external potential strengths.

Findings

Fluctuations do not change the continuous nature of the transition at high potential.

Fluctuations tend to stabilize the liquid phase in strong external potentials.

The transition changes from first order to continuous via a tricritical point with increasing potential.

Abstract

We incorporate the effects of fluctuations in a density functional analysis of the freezing of a colloidal liquid in the presence of an external potential generated by interfering laser beams. A mean field treatment, using a density functional theory, predicts that with the increase in the strength of the modulating potential, the freezing transition changes from a first order to a continuous one via a tricritical point for a suitable choice of the modulating wavevectors. We demonstrate here that the continuous nature of the freezing transition at large values of the external potential $V_{e}$ survives the presence of fluctuations. We also show that fluctuations tend to stabilize the liquid phase in the large $V_{e}$ regime.