Undissociated screw dislocation in Si: Glide or shuffle set?

Abstract

In diamond and zinc blende crystals, the competition between glide and shuffle-set slips has been intensively studied. In particular, the undissociated screw dislocation in Si seen at low temperature about five years ago was generally believed to be shuffle set. In this letter, the authors have performed tight-binding and density functional theory calculations that show that a glide-set C core has lower energy than the shuffle-set A core after period-doubling reconstruction. Since the C core can cross slip between two glide-set planes, it satisfies all the experimental observations to date, and may play important roles in dislocation cross slip and ductile-to-brittle transition in these materials. © 2006 American Institute of Physics.