2003 Volume 1 Pages 26-32
We have investigated sequential transformations among surface reconstructions during Ca adsorption on Si(111) by in-situ high-temperature scanning tunneling microscopy (STM). A series of striped superstructures, 3×1, 5×1, 7×1, and 2×1, were formed with Ca coverage increasing, but their transformation behaviors depended on the substrate temperature. From shifts of step positions during these transformations and detailed comparison among these structures coexisting in single STM images, we have confirmed that all of these striped structures should consist of regular arrangements of two kinds of Si chains, honeycomb and Seiwatz chains. Furthermore, we found that when a higher-coverage stripe nucleated in a domain of lower-coverage-stripe phase, the lower-coverage stripes shifted entirely within the domain, sweeping out the out-of-phase boundaries. We propose an atomistic model for the transformation including a sequential re-bonding of the Si chains.
