The diffusion of strontium atoms on the Si(111) surface at room temperature was investigated using scanning tunnel microscopy and simulations carried out in terms of density functional theory and the Monte Carlo method. It was found that reconstruction of a clean silicon surface with a 7 x 7 structure had a marked effect upon the diffusion process. The average velocity of motion of a strontium atom in a unit cell of the 7 x 7 structure was calculated. The main diffusion paths of a strontium atom and the corresponding activation energies were determined. It was demonstrated that the formation of scanning tunnel microscopic images of a Si(111)-7 x 7 surface with adsorbed strontium atoms was significantly affected by the shift of the electron density from the strontium atom to the nearest-neighbor silicon adatoms in the 7 x 7 structure.

Influence of the Si(111)-7 x 7 Surface Reconstruction on the Diffusion of Strontium Atoms. R.A.Zhachuk, S.A.Teys, B.Z.Olshanetsky: Journal of Experimental and Theoretical Physics, 2011, 113[6], 972-82