Phase-field crystal modeling of heteroepitaxy and exotic modes of crystal nucleation

We review recent advances made in modeling heteroepitaxy, two-step nucleation, and nucleation at the growth front within the framework of a simple dynamical density functional theory, the Phase-Field Crystal (PFC) model. The crystalline substrate is represented by spatially confined periodic potenti...

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Bibliographic Details
Published in:Journal of crystal growth 2017-01, Vol.457, p.24-31
Main Authors: Podmaniczky, Frigyes, Tóth, Gyula I., Tegze, György, Pusztai, Tamás, Gránásy, László
Format: Article
Language:English
Subjects:
A1: Solidification
Computer simulation
Crystal structure
Crystallization
Crystals
Dislocations
Growth Front Nucleation
Heteroepitaxy
Heterogeneous nucleation
Hydrodynamic theory of crystallization
Modelling
Nucleation
Phase-field crystal model
Substrates
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Summary:We review recent advances made in modeling heteroepitaxy, two-step nucleation, and nucleation at the growth front within the framework of a simple dynamical density functional theory, the Phase-Field Crystal (PFC) model. The crystalline substrate is represented by spatially confined periodic potentials. We investigate the misfit dependence of the critical thickness in the StranskiKrastanov growth mode in isothermal studies. Apparently, the simulation results for stress release via the misfit dislocations fit better to the PeopleBean model than to the one by Matthews and Blakeslee. Next, we investigate structural aspects of two-step crystal nucleation at high undercoolings, where an amorphous precursor forms in the first stage. Finally, we present results for the formation of new grains at the solid–liquid interface at high supersaturations/supercoolings, a phenomenon termed Growth Front Nucleation (GFN). Results obtained with diffusive dynamics (applicable to colloids) and with a hydrodynamic extension of the PFC theory (HPFC, developed for simple liquids) will be compared. The HPFC simulations indicate two possible mechanisms for GFN. •Critical thickness of heteroepitaxy follows the People-Bean relationship in PFC simulations.•Nucleation of the bcc phase via an amorphous precursor of liquidlike structure is predicted.•Formation of new grains at the growth front was observed in hydrodynamic model of freezing.
ISSN:0022-0248
1873-5002
DOI:10.1016/j.jcrysgro.2016.06.056