Growth and surface alloy formation of Mg on Ag(100)

X-ray induced photoemission (XPS and XAES) and low energy electron diffract ion have been used to study growth mechanisms and reaction of Mg with the A g(100) surface. At adsorption temperatures below 200 K layer-by-layer growt h has been found, which is transformed into a Stranski-Krastanov growth mod e at a surface temperature of 300 K. In the submonolayer regime a well orde red c(2 X 2) LEED pattern is observed at a coverage of 0.5 monolayers (ML). Both LEED and XPS reveal a morphological transition from the pseudomorphic ally grown monolayer to the Mg hcp structure for thicker layers. These laye rs are stable at surface temperatures below 300 K. Above this temperature d esorption sets in and finally at 420 K a Mg concentration equivalent to 0.5 ML remains, which forms a disordered Mg-Ag alloy with the topmost silver l ayer(s), as concluded from XAES. This alloy is stable to at least 750 K. (C ) 1999 Elsevier Science B.V. All rights reserved.