Picture of the month - February 2017

This AFM image of a rhenium surface is an amusing example of a typical artefact commonly observed with AFM. The size of the image is 5 x 5 micrometers. The object that is curiously reproduced identically over the whole image is an artifact due to the shape of the tip. The tip is probably broken at its very end and the surface of contact between the tip and the surface is of the order of 200 nm instead of the usual 2 nm. There is therefore a beautiful convolution effect which brings out the imprint of the tip on each small asperity of the surface. The imprint looks like the famous head in the game Pacman: he looks to the right, opening his mouth, ready to swallow the jellyfish. It seems as if the Pacman heads are multiplying as in the game just before the "game over" message.