The adsorption and diffusion of single Pb atoms on Si(111)-(7x7) surfaces were studied by scanning tunneling microscopy and first-principles density functional calculations. Scanning tunnelling microscopy experiments at 100 to 130K revealed 3 regions of preferential adsorption, inside each half-unit cell, as well as real time diffusion events between them. The stable adsorption sites were determined by first-principles calculations and by comparing simulated and measured scanning tunnelling microscopic images. The activation barriers for the motion inside the half-unit cells were calculated and measured experimentally. A very good agreement between calculations and experiments was found.

Single Adatom Adsorption and Diffusion on Si(111)-(7x7) Surfaces - Scanning Tunneling Microscopy and First-Principles Calculations. O.Custance, S.Brochard, I.Brihuega, E.Artacho, J.M.Soler, A.M.Baró, J.M.Gómez-Rodríguez: Physical Review B, 2003, 67[23], 235410 (4pp)