Nonlinear driven response of a phase-field crystal in a periodic pinning potential

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© 2009 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

2009

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Mcode

Degree programme

Language

en

Pages

011606/1-10

Series

Physical Review E, Volume 79, Issue 1

Abstract

We study numerically the phase diagram and the response under a driving force of the phase field crystal model for pinned lattice systems introduced recently for both one- and two-dimensional systems. The model describes the lattice system as a continuous density field in the presence of a periodic pinning potential, allowing for both elastic and plastic deformations of the lattice. We first present results for phase diagrams of the model in the absence of a driving force. The nonlinear response to a driving force on an initially pinned commensurate phase is then studied via overdamped dynamic equations of motion for different values of mismatch and pinning strengths. For large pinning strength the driven depinning transitions are continuous, and the sliding velocity varies with the force from the threshold with power-law exponents in agreement with analytical predictions. Transverse depinning transitions in the moving state are also found in two dimensions. Surprisingly, for sufficiently weak pinning potential we find a discontinuous depinning transition with hysteresis even in one dimension under overdamped dynamics. We also characterize structural changes of the system in some detail close to the depinning transition.

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Keywords

C-I transitions, pinned lattices, nonlinear driven response

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Citation

Achim, C. V. & Ramos, J. A. P. & Karttunen, M. & Elder, K. R. & Granato, E. & Ala-Nissilä, Tapio & Ying, S. C. 2009. Nonlinear driven response of a phase-field crystal in a periodic pinning potential. Physical Review E. Volume 79, Issue 1. P. 011606/1-10. ISSN 1539-3755 (printed). DOI: 10.1103/physreve.79.011606.