Monte Carlo simulation of growth of hard-sphere crystals on a square pattern

Abstract

Monte Carlo simulations of the colloidal epitaxy of hard spheres (HSs) on a square pattern have been performed. This is an extension of previous simulations; we observed a shrinking intrinsic stacking fault running in an oblique direction through the glide of a Shockley partial dislocation terminating its lower end in fcc (0 0 1) stacking [A. Mori, Y. Suzuki, S.i. Yanagiya, T. Sawada, K. Ito, Mol. Phys. 105 (2007) 1377], which was an answer to a question why the defect in colloidal crystals reduced by gravity [J. Zhu, M. Li, R. Rogers, W. Meyer, R. Ottewill, W. Russel, P.M. Chaikin, STS-73 Space Shuttle Crew. Nature 387 (1997) 883]. We have resolved one of the shortcomings of the previous simulations; the driving force for fcc (0 0 1) stacking, which was a stress from a small periodic boundary simulation box, has been replaced with the stress from a pattern on the bottom. We have observed disappearance of stacking fault in this realizable condition. Sinking of the center of gravity has been smooth and of a single relaxation mode under the condition that the gravitational energy mgσ is slightly less than the thermal energy k BT. In the snapshots tetrahedral structures have appeared often, suggesting formation of staking fault tetrahedra. © 2010 Elsevier B.V.