ANALYSIS AND CALIBRATION OF IN-SITU SCANNING-TUNNELING-MICROSCOPY IMAGES WITH ATOMIC-RESOLUTION INFLUENCED BY SURFACE DRIFT PHENOMENA

The influence of surface drift velocities on in situ scanning tunnelli ng microscopy (STM) experiments with atomic resolution is analysed exp erimentally and mathematically. Constant drift velocities much smaller than the speed of scanning can in many in situ STM experiments with a tomic resolution result in an apparent surface reconstruction. It is s hown that a surface atomic structure can be distorted and observed as another atomic structure entirely owing to a constant drift velocity i n the plane of the surface. The image can be resolved mathematically a nd the components of the drift velocity as well as the vectors of the non-distorted surface lattice can be determined. The calibration of di stances can thus be carried out also when the image is influenced by d rift. Results with gold surfaces and graphite surfaces are analysed an d discussed.