On the surface properties of lead structures on Au(1Â 1Â 1), an atom dynamic approach

The scanning tunneling microscope (STM), operating in an electrochemical environment, can be used to produce structures on metal electrodes. In this work, we simulate the generation of lead clusters on a Au(1 1 1) surface. By loading the tip of the STM with lead atoms, and subsequently bringing the tip in contact with the gold surface, large clusters of lead are readily produced. However, these clusters are not stable at potentials positive of the deposition potential for bulk lead. It is argued that the instability of these clusters is due to the fact that lead and gold do not form a stable alloy. There are, however, some indications that surface alloying may occur.