Nucleation Barrier for Volume-Conserving Shape Changes of Faceted Crystals |
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Authors: | William W Mullins Gregory S Rohrer |
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Affiliation: | Department of Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213–3890 |
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Abstract: | This paper considers volume-conserving shape changes of small faceted particles or cavities; these changes are driven by surface-energy reduction. If these changes require normal motion of the facets (singular surfaces), and if the perimeter free energy σp (per unit area) of a nucleus of a new facet layer is comparable to a typical surface free energy (σ∼ 1 J/m2), the energy barrier is prohibitively large for facets larger than a limiting size of approximately a nanometer unless they are intersected by dislocations that provide a source of steps. In the absence of such dislocations, particles that contain these facets are immobilized in their initial shapes. If σp < σ, the limiting facet size is increased by a factor of approximately σ/σp. |
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Keywords: | crystals/crystallization nucleation surface |
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