Surfactant effect of Pb in the growth of Fe on Cu(111): A kinetic effect

The effect of predepositing 1 ML of lead on the substrate surface in the growth of Fe on Cu(111) is studied both at room and high temperature (400 K). The results show that, even though the Pb monolayer floats efficiently over the Fe film, the thermodynamic equilibrium state of the film consists of three-dimensional iron clusters over the copper surface, and consequently, that the room-temperature surfactant action of the Pb monolayer results merely from its effect on the kinetics of the growth, in particular decreasing the mobility of the Fe atoms.