The SiC(111)-(3 x 3) phase was analyzed by scanning tunnelling microscopy, low-energy electron diffraction holography, density functional theory, and conventional low-energy electron diffraction. A single adatom per unit cell found in scanning tunneling microscopy acts as a beam splitter for the holographic inversion of discrete low-energy electron diffraction spot intensities. The resulting 3D image guides the detailed analyses by low-energy electron diffraction and density functional theory which found a Si tetramer on a twisted Si adlayer with clover-like rings. This twist model with one dangling bond left per unit cell represents a novel (n x n)-reconstruction mechanism of group-IV (111) surfaces.

Novel Reconstruction Mechanism for Dangling-Bond Minimization - Combined Method Surface Structure Determination of SiC(111)- (3 x 3). U.Starke, J.Schardt, J.Bernhardt, M.Franke, K.Reuter, H.Wedler, K.Heinz, J.Furthmüller, P.Käckell, F.Bechstedt: Physical Review Letters, 1998, 80, 758-61