A systematic study was made of the atomic and electronic structure of the Si(111)-(5 x 2)-Au reconstruction using first-principles electronic structure calculations based upon density functional theory. Previously proposed structural models were analyzed, and a completely different structure was found during the structural optimizations. The energetics and structural and electronic properties of the various models were studied in detail. For the two most stable models, the change in the surface energy was also calculated as a function of the content of silicon adatoms, for a realistic range of concentrations. The present model was the energetically most favourable one in the range of low adatom concentrations, while Erwin’s 5 x 2 model became favourable at larger adatom concentrations. The cross-over between the surface energies of the structures was found to be close to ½ adatom per 5 x 2 unit cell. This was near to the maximum adatom coverage observed in experiments. Both the present structure, and Erwin’s 5 x 2 model, seemed to provide a good description of much of the available experimental data; especially angle-resolved photo-emission measurements.

First-Principles Study of the Atomic and Electronic Structure of the Si(111)-(5 x 2)-Au Surface Reconstruction. S.Riikonen, D.Sánchez-Portal: Physical Review B, 2005, 71[23], 235423 (16pp)