Shrinking stacking fault through glide of the Shockley partial dislocation in hard-sphere crystal under gravity

TL;DR

This study uses Monte Carlo simulations to demonstrate the disappearance of stacking faults in a hard-sphere crystal under gravity, highlighting the role of Shockley partial dislocation glide and crystal strain in defect reduction.

Contribution

It provides new insights into defect dynamics in colloidal crystals under gravity, specifically the mechanism of stacking fault shrinking via Shockley partial dislocation glide.

Findings

Stacking faults can disappear through Shockley partial dislocation glide.

Crystal strain cooperates with gravity to reduce stacking faults.

Monte Carlo simulations effectively model defect dynamics under gravity.

Abstract

Disappearance of a stacking fault in the hard-sphere crystal under gravity, such as reported by Zhu et al. [Nature 387 (1997) 883], has successfully been demonstrated by Monte Carlo simulations. We previously found that a less ordered (or defective) crystal formed above a bottom ordered crystal under stepwise controlled gravity [Mori et al. J. Chem. Phys. 124 (2006) 174507]. A defect in the upper defective region has been identified with a stacking fault for the (001) growth. We have looked at the shrinking of a stacking fault mediated by the motion of the Shockley partial dislocation; the Shockley partial dislocation terminating the lower end of the stacking fault glides. In addition, the presence of crystal strain, which cooperates with gravity to reduce stacking faults, has been observed.