Partial Disorder of the Si(111)6×6-Au Surface Studied by Scanning Tunneling Microscopy

Scanning tunneling microscopy (STM) is used to investigate a 6×6 surface phase of the Au/Si(111) interface. Results show that no well-ordered structure is present on this surface. Instead, two ordered and one disordered 6×6 sublattices are observed to be formed in the distance scale of 500 A. A kinematical calculation of the diffraction patterns is carried out taking into account the difference in sublattice order. The calculation reproduces the main features of the reported electron-diffraction patterns well. The comparison of these results with those of previous structural studies is discussed.