STM study of dynamical effects on submonolayer phases of Pb/Si(111)

By means of STM we have been able to analyze in real time the complex dynam ical processes that take place at room temperature in the interface between Pb/Si(111)-(1 x 1) and 1/3 ML alpha -Pb/Si(111)-(root3 x root3)R30 degrees reconstructions. We have found that the border between these reconstructio ns is highly mobile, showing a fluctuating character between 1 x 1 regions and defect free areas presenting the alpha-(root3 x root3)R30 degrees recon struction. These fluctuations involve a large number of atoms in cooperativ e movement as well as atom recombination in the border of the two reconstru ctions. The intrinsic character of these effects versus possible STM influe nce has been analyzed and discussed, and a field-induced diffusion mechanis m is tentatively suggested. (C) 2001 Elsevier Science B.V. All rights reser ved,