Dynamics of phasons; Phase defects formed on dimer rows, and related structural changes of the Si(100) surface at 80 K studied by scanning tunneling microscopy

Type-P defects, which are mobile phase defects on dimer rows with a structure similar to that of the type-C defect, were observed on Si(100) surface at 80 K, however, the observed surface structure was mainly c(4 x 2); contrary to the previous results obtained at 6 K. Complete p(2 x 2) arrangement was unstable, and type-P defects tended to form pairs with other type-P defects on neighboring dimer rows; resulting in a reduction of the area with complete p(2 x 2) arrangement. This is the first observation of the interacting phasons; type-P defects formed on Si(100) surface. The observed results were analyzed with the Ising model, and domain boundaries between c(4 x 2) and p(2 x 2) arrangements were found to play an important role in the dynamics of type-P defects at 80 K.