On (111) oriented gold thin films it is possible to locally modify the surface by applying a voltage pulse (see eg. T. Schaub, Nanotechnology 3 (1992) p77-83). Depending on the polarity of the pulse it is possible to field evaporate tip material onto the surface.
The surface prior the applied pulses.
After applying several pulses (0-4V) using the spectroscopy feature of the easyScan STM software a deposit is visible.
For reference see e.g T. Schaub, Nanotechnology 3 (1992) p77-83View application note (PDF)