Melting In Charged Colloidal Systems

This thesis is devoted to study the melting transition in charged colloidal systems. Unliking melting transition in 3-dimension systems, melting transition in 2D systems has been in controversy for more than 20 years since the establishment of the KTHNY (Kosterlitz-Thouless-Halperin-Nelson-Young) theory. Whether 2D melting systems is a first order transtion or a two-stage continous transtion is still unclear. It may be caused by the finit-size effect of the system, beside, the specific properties of the studied system play an important role too. In this thesis, melting transition in colloidal systems in which " soft" disks interact with Yukawa potential was studied. It was turned out that melting in 3D systems is a well-known first order transition. And in 2D systems, it is a two-stage process.In the first chapter, we present a brief introduction on colloidal systems, mainly focused on forces between colloids and the phase behavior.In the second chapter, we introduced the theory of phase transion, including Landau theory and the KTHNY theory.In the third chapter, the research method of melting transiton and the establishment of the model were showed in detail. At the last of this chapter, we presented and discussed the results we obtained.A summary was made in the last chapter.