STM measurements on alloy formation during submonolayer growth of Mn on Cu 111/

Stimulated by results from work function change measurements during the epitaxial growth of Mn on Cu 111.at room temperature, this system has been studied using STM under UHV conditions. These measurements show that after reaching a substrate step the Mn atoms are incorporated into the first copper layer. After the initial formation of an alloy brim at the substrate steps this incorporation takes place only into the lower terrace. Further deposition leads to compact alloy islands existing exclusively at substrate steps and with a thickness of at least two layers. These islands exhibit a hexagonal network structure with a periodicity of about 30 A° , while on the atomic scale a 63=63.R308 superstructure is found. Annealing such films to 500 K changes the appearance of this network. With increasing temperature the structures become more and more well-ordered and the average size of the unit mesh increases. q1999 Elsevier Science B.V. All rights reserved.