Thermal fluctuations and phase diagrams of the phase-field crystal model with pinning

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© 2008 American Physical Society (APS). http://www.aps.org

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Journal Title

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Volume Title

School of Science | A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä

Date

2008

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Mcode

Degree programme

Language

en

Pages

031109/1-7

Series

Physical Review E, Volume 78, Issue 3

Abstract

We study the influence of thermal fluctuations in the phase diagram of a recently introduced two-dimensional phase field crystal model with an external pinning potential. The model provides a continuum description of pinned lattice systems allowing for both elastic deformations and topological defects. We introduce a nonconserved version of the model and determine the ground-state phase diagram as a function of lattice mismatch and strength of the pinning potential. Monte Carlo simulations are used to determine the phase diagram as a function of temperature near commensurate phases. The results show a rich phase diagram with commensurate, incommensurate, and liquidlike phases with a topology strongly dependent on the type of ordered structure. A finite-size scaling analysis of the melting transition for the c(2×2) commensurate phase shows that the thermal correlation length exponent ν and specific heat behavior are consistent with the Ising universality class as expected from analytical arguments.

Description

Keywords

order, disorder, phase transition, phase field crystal model, Monte Carlo simulations

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Citation

Ramos, J. A. P. & Granato, E. & Achim, C. V. & Ying, S. C. & Elder, K. R. & Ala-Nissilä, Tapio. 2008. Thermal fluctuations and phase diagrams of the phase-field crystal model with pinning. Physical Review E. Volume 78, Issue 3. P. 031109/1-7. ISSN 1539-3755 (printed). DOI: 10.1103/physreve.78.031109.