A Contemporary Look at the Polyhedral Shape Instability of Crystals Growing under Conditions of Diffusion‐Limited Supply of Building Material

Abstract

AbstractThis paper intends to shed fresh light on the polyhedral shape (in)stability of crystals growing under conditions of uneven diffusion supply of building material. A simplified theoretical consideration of the phenomenon is presented; the whole crystal is regarded as material consumer (but not merely a separate face on it). Accounted is for the fact that different amounts of building material are supplied by diffusion to the diverse types of crystal faces. Besides, critical sizes of crystal faces over which they lose the ability to grow macroscopically flat (because shallow cavities are formed on them) are calculated not only for the basal faces of Zn crystals growing from highly diluted own vapors mixed in inert (in respect to this metal) gases, such as H2 and Ar, but also for the pyramidal crystal faces. So, a logical explanation is given of the long‐standing problem: why the measured critical sizes of Zn single crystals grown in inert atmospheres are much smaller than the theoretically calculated critical sizes? Finally, the widths of the macroscopically flat rims surrounding the cavities on basal faces of Zn and Cd crystals (growing under conditions of uneven diffusion supply of building material) are determined in a simplified way.