Novel Self-Organized Structure of a Ag-S Complex on the Ag(111) Surface below Room Temperature

A well-ordered, self-organized dot-row structure appears after adsorption of S on Ag(111) at 200 K. This dot-row motif, which exhibits fixed spacing between dots within rows, is present over a wide range of coverage. The dots are probably Ag3S3 clusters with adsorbed S in the spaces between dots. Dynamic rearrangements are observed. Small domains of aligned dot-rows form during adsorption and grow quickly after adsorption ends. The domains also exhibit large equilibrium fluctuations after adsorption. The dot-row structure disappears reversibly upon heating above 200 K and transforms reversibly to an elongated island structure upon cooling below 200 K. DFT supports the assignment of the dots as Ag3S3 trimers and also lends insight into the possible origins of other structures observed in this complex system