Abstract
Atomic scale modification of surfaces may trigger off dynamical processes. This is shown here by using the tip of a scanning tunneling microscope to extract an individual atom in a controlled manner from a predefined site of the reconstructed Ge(111)- (2 8) surface. By thermally activated hopping of neighboring adatoms to the vacant site, the produced single-atom vacancy diffuses on the surface. From statistical analysis of the adatom configurations observed around the vacancy, we determine tiny ( 0.15 eV) differences in free energy between the configurations. A linear increase of the configuration free energy with the number of adatoms located at metastable sites is reported.
- Received 10 February 1997
DOI:https://doi.org/10.1103/PhysRevLett.80.3101
©1998 American Physical Society