Self-assembly via adsorbate-driven dislocation reactions -: art. no. 106101

Deposition of S onto a monolayer of Ag/Ru(0001) transforms the herringbone pattern of the clean Ag film into a strikingly regular array of 2D-vacancy islands [K. Pohl et al., Nature (London) 397, 238 (1999)]. Time-resolved scanning tunneling microscopy reveals that this nanometer-scale restructuring occurs by a cooperative mechanism involving the sequential formation of triangular regions with fcc and hcp stacking. Using a 2D Frenkel-Kontorova model, we can simulate the creation of these triangular building blocks via basic dislocation motions and reactions.