Rare-earth silicide thin films on the Si(111) surface

Rare-earth induced layered structures on the Si(111) surface are investigated by a combined approach consisting of ab initio thermodynamics, electron and x-ray diffraction experiments, angle-resolved photoelectron spectroscopy, and scanning tunneling microscopy. Our density functional theory calculations predict the occurrence of structures with different periodicity, depending on the rare-earth availability. Microscopic structural models are assigned to the different silicide phases on the basis of stability criteria. The thermodynamically stable theoretical models are then employed to interpret the experimental results. The agreement between the simulated and measured scanning tunneling microscopy images validates the proposed structural models. The electronic properties of the surfaces are discussed on the basis of the calculated electronic band structure and photoelectron spectroscopy data.