**Kinetic coefficient of steps at the Si(111) crystal-melt interface from
molecular dynamics simulations**

D Buta and M Asta and JJ Hoyt, JOURNAL OF CHEMICAL PHYSICS, 127, 074703 (2007).

DOI: 10.1063/1.2754682

Nonequilibrium molecular dynamics simulations are applied to the
investigation of step-flow kinetics at crystal-melt interfaces of
silicon, modeled with the Stillinger-Weber potential **Phys. Rev. B 31,
5262 (1985)**. Step kinetic coefficients are calculated from
crystallization rates of interfaces that are vicinals of the faceted
(111) orientation. These vicinal interfaces contain periodic arrays of
bilayer steps, and they are observed to crystallize in a step-flow
growth mode at undercoolings lower than 40 K. Kinetic coefficients for
both **110** and **121** oriented steps are determined for several values of
the average step separation, in the range of 7.7-62.4 A. The values of
the step kinetic coefficients are shown to be highly isotropic, and are
found to increase with increasing step separation until they saturate at
step separations larger than similar to 50 A. The largest step kinetic
coefficients are found to be in the range of 0.7-0.8 m/(sK), values that
are more than five times larger than the kinetic coefficient for the
rough (100) crystal-melt interface in the same system. The dependence of
step mobility on step separation and the relatively large value of the
step kinetic coefficient are discussed in terms of available theoretical
models for crystal growth kinetics from the melt. (c) 2007 American
Institute of Physics.

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