The surface modification of thin films during H absorption was investigated at the nm-scale by means of scanning tunnelling microscopy. Two different types of surface pattern appeared and were attributed to H-induced plastic deformation processes within the film. Disc-like islands were first formed due to GdH2 precipitation and the concomitant emission of extrinsic dislocation loops. At a later stage, ramps appeared on the surface as a result of glide displacements which originated from misfit dislocations at the interface between the substrate and the thin film.

H-Induced Plastic Deformation of Gd Thin Films Studied by STM. A.Pundt, M.Getzlaff, M.Bode, R.Kirchheim, R.Wiesendanger: Physical Review B, 2000, 61[15], 9964-7