Deposition of 0.2-0.4 ML of gold on Si(111) at about 6000C results in a very nice reconstruction. From the LEED pattern it appears to be 5x1, whereas STM clearly shows 5x2 structure (that's the reason for "5x1" notation). STM tip seems to be able to pick up a gold atom into a stable configuration, which of course makes atomic resolution imaging possible.
75x25 nm2 STM image (derivative mode)
On the above image 3 types of features are clearly seen.
- First of course the actual 5x2 rows
- Second - prominent protrusions on top of the rows
they are associated with extra gold atoms and have smallest spacing 4a along the rows - Third - at the edge of each row there's a string of smaller protrusions
spacing of these small protrusions corresponds to the 5x2 periodicity
The following image shows a 3D view of the same surface.
All these images of course are very nice, but are these rows indeed one-dimensional?
Go on to the photoemission results.
