2007/09/30 by Wei-Kai Qi, Shao-Meng Qin, Xiaoying Zhao +2
Materials Science · Physics and Astronomy · #Brownian motion #Condensed matter physics #Isotropy #Material Dynamics and Properties #Materials science #Phase (matter) #Phase diagram #Physics #Quantum mechanics #Spectroscopy and Quantum Chemical Studies #Theoretical and Computational Physics #Yukawa potential #cond-mat.soft #cond-mat.stat-mech
paper · pdf · doi:10.1088/0953-8984/20/24/245102
published as J. Phys.: Condens. Matter 20, 245102 (2008) · 9 pages, 8 figures. any comments are welcome
openalex publication_date 2008/05/22 · arxiv created 2008/09/03 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We performed Brownian-dynamics simulations on the melting of two-dimensional colloidal crystals in which particles interact via a Yukawa potential. A stable hexatic phase was found in the Yukawa systems, but we also found that the melting of Yukawa systems is a two-stage melting, which is inconsistent with the Kosterlitz–Thouless–Halperin–Nelson–Young (KTHNY) theory. A two-phase coexistence region between the stable hexatic phase and the isotropic liquid phase was found. The behavior of point defects in the coexistence region is very complicated. The emergence of some unstable free disclinations and grain boundaries was a characteristic representative of the isotropic liquid phase, and a large number of free dislocations indicated the existence of a hexatic phase. This indicates the existence of a phase of hexatic–isotropic liquid phase coexistence. The big picture in the melting of a two-dimensional Yukawa system is that first the system undergoes a transition induced by the formation of free dislocations, then it goes through a phase coexistence, and finally, it comes into an isotropic fluid phase. This melting process is consistent with experiments and simulations.