Confined Ge-Pt states in self-organized Pt nanowire arrays on Ge(001)

By means of band structure calculations within the density functional theory and the generalized gradient approximation, we investigate the electronic structure of self-organized Pt nanowires on the Ge(001) surface. In particular, we deal with a novel one-dimensional surface state confined in the nanowire array and clarify its origin. Due to large Pt contributions, the novel state is rather a mixed Ge-Pt hybrid state than a confined Ge surface state. Moreover, we compare our results to data from scanning tunneling microscopy.