Geometrical defects in two-dimensional melting of many-particle Yukawa systems

TL;DR

This study uses Langevin dynamics simulations and polygon analysis to explore how geometrical defects influence the melting and freezing transitions in two-dimensional Yukawa particle systems.

Contribution

It introduces a polygon construction method to characterize 2D melting, revealing defect proliferation patterns and vertex type behaviors during phase transitions.

Findings

Quadrilaterals remain temperature-independent in the liquid phase.

Number of pentagons increases linearly with temperature.

Vertex type concentrations peak at critical transition points.

Abstract

We perform Langevin dynamics simulations and use polygon construction method to investigate two-dimensional (2D) melting and freezing transitions in many-particle Yukawa systems. 2D melting transitions can be characterized as proliferation of geometrical defects - non-triangular polygons, obtained by removing unusually long bonds in the triangulation of particle positions. A 2D liquid is characterized by the temperature-independent number of quadrilaterals and linearly increasing number of pentagons. We analyze specific types of vertices, classified by the type and distribution of polygons surrounding them, and determine temperature dependencies of their concentrations. Critical points in a solid-liquid transition are followed by the peaks in the abundances of certain types of vertices.