Background: Scanning Tunneling Microscopy
1. Imaging of surface and atoms and molecules on surfaces with atomic-scale spatial resolution.
2. Measure energy-resolved (spectroscopic) information on single atoms and molecules.
3. Move atoms and molecules on surfaces and build nanostructures with exact control over the position of atoms.
Figure 1 shows an example of the fantastic imaging capabilities of STM. Here we were working on iron atoms on a two-layer thick film of insulating MgO, which was grown on a silver substrate. Each one of the mountains is a single iron atom, while each of the small bumps in a regular square pattern is a single oxygen atom of the top layer of MgO. This image was obtained with a very special tip in order to give this high spatial resolution.
Figure 1: Two iron atoms sitting on a surface of a thin film of magnesium-oxide (MgO). A special tip, functionalized with hydrogen, was used to obtain atomic resolution of the oxygen atoms of the MgO surface layer. Image size: (4 nm)2, image obtained with our “Alice” STM system.