Crystallization of fcc (111) and (100) crystal-melt interfaces: A comparison by molecular dynamics for the Lennard-Jones system
The crystal growth rates of Lennard-Jones fcc (face-centered cubic) (111) and (100) faces into the melt have been studied as a function of undercooling by molecular dynamics. The (100) grows without activation energy barrier at rates determined by the difference in the free energies of the crystal and melt phases, and the arrival rate of atoms across a plane determined from the kinetic theory of gases. The maximum velocity occurs at approximately half the melting point and represents 80 m/s for argon. The (111), on the other hand, grows at rates two to three times lower than this; the exact rate being size dependent. The growth kinetics are now activated and resemble Wilson--Frenkel behavior. However, the step responsible for such activation is not the simple liquid diffusion of Wilson--Frenkel theory, but rather the concerted motion of atoms at the interface selecting either all fcc or all hcp (hexagonal close packed) triangular lattice sites before a layer can grow.
- Research Organization:
- Department of Materials Science, S.U.N.Y. Stony Brook, Stony Brook, New York 11794
- OSTI ID:
- 6990115
- Journal Information:
- J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 89:2; ISSN JCPSA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
CRYSTAL GROWTH
CRYSTALLIZATION
CRYSTALS
DIFFUSION
FLUIDS
INTERFACES
LENNARD-JONES POTENTIAL
LIQUIDS
PHASE TRANSFORMATIONS
POTENTIALS
SIMULATION
TRIPLE POINT