Coexistence of hexatic and isotropic phases in two-dimensional Yukawa systems

TL;DR

This study uses Brownian dynamics simulations to investigate melting behavior in two-dimensional Yukawa systems, revealing coexistence of isotropic and hexatic phases and challenging the traditional KTHNY melting theory.

Contribution

It demonstrates the coexistence of hexatic and isotropic phases in Yukawa systems, showing a two-stage melting process that differs from KTHNY theory.

Findings

Coexistence of hexatic and isotropic phases observed.

Melting occurs via a two-stage process, not matching KTHNY.

Point defects in Yukawa systems were studied.

Abstract

We have performed Brownian dynamics simulations on melting of two-dimensional colloidal crystal in which particles interact with Yukawa potential. The pair correlation function and bond-orientational correlation function was calculated in the Yukawa system. An algebraic decay of the bond orientational correlation function was observed. By ruling out the coexistence region, only a unstable hexatic phase was found in the Yukawa systems. But our work shows that the melting of the Yukawa systems is a two-stage melting not consist with the KTHNY theory and the isotropic liquid and the hexatic phase coexistence region was found. Also we have studied point defects in two-dimensional Yukawa systems.