Structure of the Mn-induced Cu(100) c(2x2) surface - Comment

We have studied the atomic arrangement of Mn upon deposition on Cu(100) at room temperature using low-energy electron diffraction (LEED) and scanning tunneling microscopy (STM). Scanning tunneling microscopy reveals that Mn is already incorporated at very low coverages (similar to 0.005 ML Mn). Both LEED and STM show that the surface alloy is characterized by a considerable corrugation where Mn atoms are displaced outside by 0.30 Angstrom. Our findings are at variance with a recent STM study [Phys. Rev. B 52, 2735 (1994)] which reports a corrugation of approximately 0.12 Angstrom and claims Mn incorporation only above a critical Mn coverage which should be larger than 0.06 ML.