Formation and coalescence of surface domains introduced by metal deposition on a stepped Si(111) surface

By depositing sub-monolayer Au atoms onto a stepped Si(111)-(7$\times$7) surface at 600$^{\circ}$C, stripes of (5$\times$2) domain form on the upper step edges of most terraces. Upon continued annealing at a higher temperature, most of the terraces transform into either Au-free (7$\times$7) terraces or fully reconstructed (5$\times$2) terraces. After analyzing the distance distribution between neighboring (5$\times$2) terraces we detect the presence of an optimal distance separating (5$\times$2) terraces. This optimal distance, controllable via the Au coverage, can be explained by the minimization of long-range strain relaxation energy of a system consisted of alternating domains. The ability of tuning surface domain structure through metal deposition provides a new way of manipulating surface morphology in the nanometer-scale range.