Metals such as Au deposited on graphite substrates were found to migrate very easily when biased in scanning tunnelling microscopes. Depending upon the film thickness and the tip voltage, a hillock surrounded by grooves or a hole surrounded by hillocks with a height of approx. ±10nm and a lateral dimension of about 100nm were formed. The mechanism of these surface-modification phenomena was discussed in light of electro- and thermomigration.

Migration of Metals on Graphite in Scanning Tunneling Microscopy. Ohto, M., Yamaguchi, S., Tanaka, K.: Japanese Journal of Applied Physics – 2, 1995, 34[6A], L694-7