Influence of Ag adsorbate on the Si( 111) - fi X &(Au, Cu) structure

The interaction of Ag adsorbate and the Sic11 l)- 6 X fi-(Au, C u ) su rf ace has been studied by means of LEED-AESRRS techniques. A Ag film deposited onto the Si(lll>-fi X J?;-(Au, C u ) su rf ace at RT is examined by isochronal annealing at several temperatures. The Ag/Si(l 1 l)- fi X &-(Au, Cu) surface shows a clear 26 X 2fi LEED pattern on annealing at 250°C. The 2& X 2& LEED pattern persists instead of &i X fi or fi X fi, even when the Ag coverage decreases to 0.3 ML. These results suggest that the 26 X 2fi-(Au, Ag, Cu) structure has been newly produced for the first time in this experiment.