The development of order in a system of metal clusters

Domain growth and the motion of grain boundaries are important processes in materials science. The behavior of grain boundaries and other boundaries between different domains is tied to many material properties, such as conductivity. In dilute systems, one boundary of interest is the domain wall between the material and vacuum. Thermodynamically unstable systems will show domain, i.e. cluster growth. This cluster growth can be studied directly by high resolution scanning transmission electron microscopy (STEM).We have examined a system of gold clusters, prepared by in vacuo vapordeposition of gold on thin amorphous carbon substrates. A complete description of methods may be found in reference 1.By simultaneously depositing metal atoms with an easily removed hydrocarbon layer, we observed small clusters (figure la.) which grew in situ without further deposition under clean conditions at room temperature in the microscope column (figure lb.). The initial projected area distribution (seen in figure 2a.) showed a good fit to a Poisson distribution of areas.