Atomic geometry of Ge(111) √3 × √3R30°-Ag determined by low-energy electron diffraction

We have carried out a quantitative low-energy electron-diffraction intensity analysis of the Ge(111) {}3 ×{} {}3 R30^∘{}-Ag structure. It is found that the Ag atoms arrange according to a honeycomb chained trimer model (HCT) similar to the situation of Si(111) {}3 ×{} {}3 R30^∘{}-Ag. This result shows that the Ge-Ge bond is stronger than the Ag-Ag bond on the surface, thus causing the HCT structure to form.