Structural Disorder of Si(111)√3×√3-Au Surface Studied by LEED

LEED observation and analysis of the submonolayer interfaces of Au/Si(111) have been reported. It is shown that a well-ordered √3×√3 surface is not formed in this system. Instead, unusual √3×√3 LEED patterns appear with either diffuse, sharp and diffuse or sharp and ring-like spots depending on Au coverage. A kinematical analysis of the LEED patterns for various Au coverages implies that the unusual √3×√3 patterns are due to early stages of the formation of a 6×6 surface.