Structural model of the Au-induced Si(553) surface: Double Au rows

A structural model of Au induced Si(553) surface is proposed. The model is based on the recently revised value of Au coverage of 0.48 monolayers, which suggests the formation of two gold chains on each Si(553) terrace. The resulting structural model, such as the models of other vicinal Si surfaces, features the honey-comb chain, but no buckling of the step edge is observed, unlike in the case of the Si(335)-Au and Si(557)-Au surfaces. The present model is more stable than the models with single Au chain only, and agrees well with existing experimental data. In particular, calculated band structure, featuring two metallic bands coming from the hybridization of gold in both chains with neighboring Si atoms, matches well the photoemission data. Moreover, theoretical scanning tunneling microscopy topographs remain in good agreement with the experiment.