Thermodynamics of bcc metals in phase-field-crystal models

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Journal Title
Journal ISSN
Volume Title
School of Science | A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Date
2009
Major/Subject
Mcode
Degree programme
Language
en
Pages
031602/1-10
Series
Physical Review E, Volume 80, Issue 3
Abstract
We examine the influence of different forms of the free-energy functionals used in the phase-field-crystal (PFC) model, and compare them with the second-order density-functional theory (DFT) of freezing, by using bcc iron as an example case. We show that there are large differences between the PFC and the DFT and it is difficult to obtain reasonable parameters for existing PFC models directly from the DFT. Therefore, we propose a way of expanding the correlation function in terms of gradients that allows us to incorporate the bulk modulus of the liquid as an additional parameter in the theory. We show that this functional reproduces reasonable values for both bulk and surface properties of bcc iron, and therefore it should be useful in modeling bcc materials. As a further demonstration, we also calculate the grain boundary energy as a function of misorientation for a symmetric tilt boundary close to the melting transition.
Description
Keywords
free energy, density functional theory, correlation functions, anisotropy, liquid crystals
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Citation
Jaatinen, A. & Achim, C. V. & Elder, K. R. & Ala-Nissilä, Tapio. 2009. Thermodynamics of bcc metals in phase-field-crystal models. Physical Review E. Volume 80, Issue 3. P. 031602/1-10. ISSN 1539-3755 (printed). DOI: 10.1103/physreve.80.031602.