2003 Fiscal Year Final Research Report Summary
Growth dynamics and pattern formation of ice and CCl4 crystals under pressure
| Project/Area Number |
13640335
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
固体物性Ⅰ(光物性・半導体・誘電体)
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| Research Institution | Osaka City University |
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Principal Investigator |
MARUYAMA Minoru Osaka City University, Department of Physics, Lecturer, 大学院・理学研究科, 講師 (60117976)
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| Project Period (FY) |
2001 – 2003
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| Keywords | crystal growth / pattern formation / ice / high pressure / surfaces and interfaces / roughening transition / non-equilibrium / 非平衡 |
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| Research Abstract |
Equilibrium crystal shapes are uniquely defined by the Wulff construction that gives a minimization of the total, orientation-dependent, surface free energy for a fixed volume. Thus, the low energy orientations dominate the shape. On the other hand, growth and melt shapes near equilibrium are determined by surface orientation dependent kinetics. The slowest growing orientations ultimately dominate the asymptotic growth shape, leaving a fully faceted molecularly smooth orientations, whereas the fastest melt orientations dominate the steady state melt shapes. Using a high pressure anvil cell we produced ice crystals and examined the growth-melt asymmetry in crystal shape.
Above a roughening temperature an equilibrium shape is a partially-faceted disk. We found asymmetry between growth and melt shapes of the disk crystal ; (a) the vicinal surfaces gradually decay during growth but develop during melting ; (b) the rough surfaces grow with decreasing curvature but melt with increasing curvature while grow or melt linearly with time. These results may be due to the different kinetics between the molecular attachment and detachment processes.
Below a roughening temperature we observe that while the two dimensional steady melt shapes of ice are bounded by six planes, the similarity with faceted growth shapes is cosmetic ; the planes are not proper facets but rotated 30 degrees from the prism facets. The dynamics is described quantitatively using a geometric model for the melt-growth shape evolution.
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