This paper shows that the nanostructures deposited at room temperature in scanning tunneling microscopy experiments are produced by mechanical contact between tip and sample. Gold mounds are deposited in gold substrates and it is observed that the current flowing between tip and sample is quantized and the resistance can be as low as 100 Ω.

• Received 19 April 1993

DOI:https://doi.org/10.1103/PhysRevLett.71.1852