Real-Space Determination of Atomic Structure of the Si(111)-$\sqrt{3}\times \sqrt{3}R30°$-Au Surface by Low-Energy Alkali-Ion Scattering

The Si(111)-$\sqrt{3}\times \sqrt{3}R30°$-Au structure has been analyzed by low-energy alkali-ion-scattering spectroscopy. It has been derived that (1) Au triplet clusters form the $\sqrt{3}\times \sqrt{3}R30°$ lattice and (2) the Si first layer of honeycomb structure lies slightly below the Au layer.