Phase diagram and commensurate-incommensurate transitions in the phase field crystal model with an external pinning potential
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© 2006 American Physical Society (APS). http://www.aps.org
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Date
2006
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en
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021104/1-8
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Physical Review E, Volume 74, Issue 2
Abstract
We study the phase diagram and the commensurate-incommensurate transitions in a phase field model of a two-dimensional crystal lattice in the presence of an external pinning potential. The model allows for both elastic and plastic deformations and provides a continuum description of lattice systems, such as for adsorbed atomic layers or two-dimensional vortex lattices. Analytically, a mode expansion analysis is used to determine the ground states and the commensurate-incommensurate transitions in the model as a function of the strength of the pinning potential and the lattice mismatch parameter. Numerical minimization of the corresponding free energy shows reasonable agreement with the analytical predictions and provides details on the topological defects in the transition region. We find that for small mismatch the transition is of first order, and it remains so for the largest values of mismatch studied here. Our results are consistent with results of simulations for atomistic models of adsorbed overlayers.Description
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two-dimensional crystal lattice, pinning potential, transition
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Citation
Achim, C. V. & Karttunen, M. & Elder, K. R. & Granato, E. & Ala-Nissilä, Tapio. & Ying, S. C. 2006. Phase diagram and commensurate-incommensurate transitions in the phase field crystal model with an external pinning potential. Physical Review E. Volume 74, Issue 2. P. 021104/1-8. ISSN 1539-3755 (printed). DOI: 10.1103/physreve.74.021104.