STM study of dynamical effects on submonolayer phases of Pb/Si(1 1 1)

By means of STM we have been able to analyze in real time the complex dynamical processes that take place at room temperature in the interface between Pb/Si(1 1 1)-(1×1) and 1/3 ML α-Pb/Si(1 1 1)-(√3×√3)R30° reconstructions. We have found that the border between these reconstructions is highly mobile, showing a fluctuating character between 1×1 regions and defect free areas presenting the α-(√3×√3)R30° reconstruction. These fluctuations involve a large number of atoms in cooperative movement as well as atom recombination in the border of the two reconstructions. The intrinsic character of these effects versus possible STM influence has been analyzed and discussed, and a field-induced diffusion mechanism is tentatively suggested.