In the article in Materials Today we have illustrated how fast-scanning STM can be successfully applied to studies of dynamic processes on surfaces. Some movies from our old pages are available below.
Several terraces of the Cu(110) surface are visible, separated by monoatomic steps. As the oxygen exposure is increased, the removal of Cu atoms from the step edges is clearly observed, and simultaneously an anisotropic growth of added rows consisting of Cu-O- segments along the [001] direction takes place on the terraces.
This movie (1.5 Mb) is taken over an area of 235x256 Å2. The speed was 5 sec/image.
A magnified version (6 Mb) is also available.
It has been shown how fast-scanning, variable-temperature STM is able to directly visualize the vivid diffusion of atoms, molecules and clusters on surfaces. We can illustrate this for the diffusion of Pt adatoms on the reconstructed Pt(110)-(1×2) surface, in which every second close-packed row is missing. Insight into the atomistics of the one-dimensional, random-walk migration of the deposited Pt adatoms was obtained by acquiring many consecutive STM images played back as an STM movies.
The movie (1 Mb) shows an area of 140x140 Å2 taken at a speed of 13 sec/image at a temperature of 61 C.
Very little is known about the diffusion of defects on transition-metal oxide surfaces, but recent STM dynamics studies resulted in unprecedented, new insight into this important problem. The model system studied was the rutile TiO2(110) surface. The distinct surface features, imaged as the bright spots observed between Ti rows, are assigned to vacancy point defects (missing oxygen atoms) in the bridging oxygen.
A movie (3.9 Mb) show the vacancy jumps in a big area
A smaller region (0.7 Mb) may also be seen.
Insight into the complex dynamics of large molecules on surfaces is an essential prerequisite for controlling the synthesis of molecular nanostructures with potential applications in emerging fields such as molecular electronics and nanomechanical sensors. We have investigated how the orientation and shape of large and complex organic molecules may influence their dynamics. The test molecule known as Violet Lander (VL, C108H104) was thermally evaporated onto a Cu(110) surface.
The movie covers an area of 300x300 Å2 and was recorded at 15 sec/image.
