Structural and electronic properties of chain-like structures formed by mixed PbAl dimers on Si(001) — Computational DFT study

The energetics as well as structural and electronic properties of one-dimensional chains composed of mixed PbAl ad-dimers on the Si(001) surface are investigated using density functional theory. It is shown that the mixed PbAl ad-dimer chains are always energetically more stable than the corresponding homogenous Pb or Al chain configurations. This agrees with available experimental data but contradicts earlier theoretical results. It is also demonstrated that while the isolated mixed dimers and trimers are metallic, the longer chains tend to form semiconducting structures.