Role of the Si-Si bond stability in the first stages of Ti diffusion on a Si(1 1 1) 2 × 1 surface. A periodic DFT study

► Ti adsorption on a bare Si(1 1 1) surface. ► Ti forms polar covalent bonds with Si atoms on the surface. ► At low temperature, a stable TiSi monolayer is formed by Ti deposition on the Si(1 1 1) surface. ► Remaining Si-Si bonds in the TiSi interface play an important role for the Ti diffusion on the Si(1 1 1) surface.