Thermal vibrations of a two-dimensional self-assembled nano-array

observed by time-resolved STM

Perfectly ordered triangular lattice of vacancy islands, 25 Å across and 53 Å apart, formed by exposing a single monolayer of Ag on Ru(0001) to sulfur at room temperature in UHV.

raw data: 70 x 70 nm2 images taken 20s apart

contrast enhanced
vacancy island center-of-mass positions

Dilute gas of Ag vacancy islands at low sulfur coverage (less than 0.05 ML)

50 x 50 nm2 STM images taken 48 s apart

random net displacement of isolated islands: 65 Å per frame

effective island hop rate: 0.1 per second