Melting of a finite-sized two-dimensional colloidal crystal

Sayuri Tanaka, Yuma Oki, Yasuyuki Kimura

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

We have studied the melting process of a finite-sized two-dimensional colloidal crystal by video microscopy. The local area fraction φ and the local hexatic orientational order parameter ψ6 have been evaluated for respective Voronoi cells in the crystal. The histogram of φ exhibits a peak and the peak φ continuously decreases with the time elapsed. The histogram of |ψ6| shows an abrupt broadening for φ<0.65. This critical value of φ is the transition point between the hexatic and dense liquid phases in finite crystal. We have also evaluated φ and |ψ6| as a function of the distance from the center of the crystal r. φ(r) is almost constant within the crystal and monotonously decreases with the time elapsed. |ψ6(r)| gradually decreases with r but there is the core with |ψ6|=1 at earlier time stage. The temporal change of the average φ within the crystal is qualitatively explained by the slow diffusion of the particles situated at the crystal edge. The steric repulsion between the particles within the crystal enhances the expansion rate of the crystal edge. Overall melting behavior is same in the crystals with different sizes. We have also studied the melting of a finite-sized crystal composed of soft-core particles by Brownian dynamics simulation and verified the finite-size effect on the melting process. The simulated behavior is qualitatively in good agreement with the experimental results.

Original languageEnglish
Article number052305
JournalPhysical Review E - Statistical, Nonlinear, and Soft Matter Physics
Volume89
Issue number5
DOIs
Publication statusPublished - May 9 2014

Fingerprint

Melting
Crystal
melting
crystals
histograms
Decrease
Histogram
Voronoi Cell
Brownian Dynamics
Finite Size Effects
transition points
Dynamic Simulation
Microscopy
Order Parameter
Critical value
liquid phases
Liquid
microscopy
expansion
Experimental Results

All Science Journal Classification (ASJC) codes

  • Statistical and Nonlinear Physics
  • Statistics and Probability
  • Condensed Matter Physics

Cite this

Melting of a finite-sized two-dimensional colloidal crystal. / Tanaka, Sayuri; Oki, Yuma; Kimura, Yasuyuki.

In: Physical Review E - Statistical, Nonlinear, and Soft Matter Physics, Vol. 89, No. 5, 052305, 09.05.2014.

Research output: Contribution to journalArticle

@article{6fa23617a7784bfb853504ca4f680e33,
title = "Melting of a finite-sized two-dimensional colloidal crystal",
abstract = "We have studied the melting process of a finite-sized two-dimensional colloidal crystal by video microscopy. The local area fraction φ and the local hexatic orientational order parameter ψ6 have been evaluated for respective Voronoi cells in the crystal. The histogram of φ exhibits a peak and the peak φ continuously decreases with the time elapsed. The histogram of |ψ6| shows an abrupt broadening for φ<0.65. This critical value of φ is the transition point between the hexatic and dense liquid phases in finite crystal. We have also evaluated φ and |ψ6| as a function of the distance from the center of the crystal r. φ(r) is almost constant within the crystal and monotonously decreases with the time elapsed. |ψ6(r)| gradually decreases with r but there is the core with |ψ6|=1 at earlier time stage. The temporal change of the average φ within the crystal is qualitatively explained by the slow diffusion of the particles situated at the crystal edge. The steric repulsion between the particles within the crystal enhances the expansion rate of the crystal edge. Overall melting behavior is same in the crystals with different sizes. We have also studied the melting of a finite-sized crystal composed of soft-core particles by Brownian dynamics simulation and verified the finite-size effect on the melting process. The simulated behavior is qualitatively in good agreement with the experimental results.",
author = "Sayuri Tanaka and Yuma Oki and Yasuyuki Kimura",
year = "2014",
month = "5",
day = "9",
doi = "10.1103/PhysRevE.89.052305",
language = "English",
volume = "89",
journal = "Physical Review E",
issn = "2470-0045",
publisher = "American Physical Society",
number = "5",

}

TY - JOUR

T1 - Melting of a finite-sized two-dimensional colloidal crystal

AU - Tanaka, Sayuri

AU - Oki, Yuma

AU - Kimura, Yasuyuki

PY - 2014/5/9

Y1 - 2014/5/9

N2 - We have studied the melting process of a finite-sized two-dimensional colloidal crystal by video microscopy. The local area fraction φ and the local hexatic orientational order parameter ψ6 have been evaluated for respective Voronoi cells in the crystal. The histogram of φ exhibits a peak and the peak φ continuously decreases with the time elapsed. The histogram of |ψ6| shows an abrupt broadening for φ<0.65. This critical value of φ is the transition point between the hexatic and dense liquid phases in finite crystal. We have also evaluated φ and |ψ6| as a function of the distance from the center of the crystal r. φ(r) is almost constant within the crystal and monotonously decreases with the time elapsed. |ψ6(r)| gradually decreases with r but there is the core with |ψ6|=1 at earlier time stage. The temporal change of the average φ within the crystal is qualitatively explained by the slow diffusion of the particles situated at the crystal edge. The steric repulsion between the particles within the crystal enhances the expansion rate of the crystal edge. Overall melting behavior is same in the crystals with different sizes. We have also studied the melting of a finite-sized crystal composed of soft-core particles by Brownian dynamics simulation and verified the finite-size effect on the melting process. The simulated behavior is qualitatively in good agreement with the experimental results.

AB - We have studied the melting process of a finite-sized two-dimensional colloidal crystal by video microscopy. The local area fraction φ and the local hexatic orientational order parameter ψ6 have been evaluated for respective Voronoi cells in the crystal. The histogram of φ exhibits a peak and the peak φ continuously decreases with the time elapsed. The histogram of |ψ6| shows an abrupt broadening for φ<0.65. This critical value of φ is the transition point between the hexatic and dense liquid phases in finite crystal. We have also evaluated φ and |ψ6| as a function of the distance from the center of the crystal r. φ(r) is almost constant within the crystal and monotonously decreases with the time elapsed. |ψ6(r)| gradually decreases with r but there is the core with |ψ6|=1 at earlier time stage. The temporal change of the average φ within the crystal is qualitatively explained by the slow diffusion of the particles situated at the crystal edge. The steric repulsion between the particles within the crystal enhances the expansion rate of the crystal edge. Overall melting behavior is same in the crystals with different sizes. We have also studied the melting of a finite-sized crystal composed of soft-core particles by Brownian dynamics simulation and verified the finite-size effect on the melting process. The simulated behavior is qualitatively in good agreement with the experimental results.

UR - http://www.scopus.com/inward/record.url?scp=84900432730&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84900432730&partnerID=8YFLogxK

U2 - 10.1103/PhysRevE.89.052305

DO - 10.1103/PhysRevE.89.052305

M3 - Article

AN - SCOPUS:84900432730

VL - 89

JO - Physical Review E

JF - Physical Review E

SN - 2470-0045

IS - 5

M1 - 052305

ER -