Multiplication of threading dislocations in strained metal films under sulfur exposure

Strained thin films often contain ordered networks of misfit dislocations w hich can determine their chemical and mechanical properties. We consider th e reaction of sulfur with two-monolayer films of Cu on Ru(0001). These film s contain a network of parallel partial dislocations, separating regions of fcc and hcp stacking, with threading edge dislocations where partial dislo cations meet. Sulfur reacts with the threading dislocations and dissociates them. The increase in the threading dislocation density is accommodated by modifying the dislocation network. (C) 1999 Elsevier Science B.V. All righ ts reserved.