How Much Information is in an STM Image?*

Scanning tunneling microscope (STM) images contain a wealth of information. We are developing real-space post-processing image analysis tools to extract information that would otherwise be hidden. We use decanethiol self-assembled monolayers (SAMs) on Au(111) as our model system. We demonstrate measurements of the “molecule” locations that are in principle accurate to less than 1 pm in any direction. By creating an averaged unit cell image from many imaged unit cells, we also demonstrate that the unit cell image has no additional symmetry beyond its lattice symmetry. Average unit cell images from different structural domains of the same image demonstrate which image features are due to the surface and which are due to the tip. Time-lapse image series of SAMs allow for time averaging techniques to be used to track and study individual molecules.