Study on tip-substrate interactions by STM and APFIM.

Processes occurring at the interface of two materials coming in contact, separating or moving with respect to each other have been studied with the scanning tunnelling microscope (STM) and atom-probe (AP) field ion microscopy (APFIM). STM probe tips have been first characterised by field ion microscopy (FIM), brought into well-defined contact in the STM and afterwards inspected by time-of-flight AP. The results from mechanical contact and indentation experiments, showing material transfer and neck formation, are in reasonable good agreement with computer-based simulations on metal tip-surface interactions.