Interactions Between Ag Atoms Adsorbed At Si(111)-(7x7) Surface At Room Temperature

In this thesis,“super clean” Si(111)-(7x7) reconstruction surfaces have beensuccessfully fabricated by combining the Ar+etching and direct heating techniques.High resolution images of Ag atoms or pairs adsorbed on this kind super clean Sisurface have been obtained at room temperature by ultra high vacuum scanningtunneling microscopy (STM) with constant current mode. A analysis method has beendeveloped to measure the appearance heights of the individual Ag atoms on thesurface with the precision of about0.005angstrom. The interactions between the Agatoms on the surface have been derived from the changes of the appearance heightsfor the Ag atoms within various configurations. It is found that the interactionsbetween the Ag atoms can be described as substrate-mediated long-range interactions.Such interactions are available up to25angstrom in the range and smaller than10meV at room temperature.