DYNAMICS OF PHASONS - PHASE DEFECTS FORMED ON DIMER ROWS, AND RELATEDSTRUCTURAL-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 st ructure 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 pai rs 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 o n Si(100) surface. The observed results were analyzed with the Ising m odel, 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 defect s at 80 K.