Double Au rows on Si(553) surface

A new structural model of Au induced Si(553) surface is proposed. The model accounts for recently experimentally found value of the Au coverage, i.e. 0.48 monolayer, which suggests formation of two gold chains on each Si(553) terrace. The resulting structural model, like the models of other vicinal Si surfaces, features the honey-comb chain, but there is no buckling at step edge, which is observed on Si(335)-Au and Si(557)-Au surfaces. The present model is more stable than the models with single Au chain only, and agrees very well with existing experimental data. In particular, calculated band structure, featuring two metallic bands coming from hybridization of the gold in both chains with neighboring Si atoms, perfectly matches the photoemission data. Moreover, theoretical scanning tunneling microscopy topography remains in excellent agreement with the experiment.