Abstract
We present here a comprehensive search for the structure of the Si(553)-Au reconstruction. More than 200 different trial structures have been studied using first-principles density-functional calculations with the SIESTA code. An iterative procedure, with a step-by-step increase in the accuracy and computational cost of the calculations, was used to allow for the study of this large number of configurations. We have considered reconstructions restricted to the topmost bilayer and studied two types: (i) ``flat'' surface-bilayer models, where atoms at the topmost bilayer present different coordinations and registries with the underlying bulk, and (ii) nine different models based on the substitution of a silicon atom by a gold atom in different positions of a $\ensuremath{\pi}$-bonded chain reconstruction of the Si(553) surface. We have developed a compact notation that allows us to label and identify all these structures. This is very useful for the automatic generation of trial geometries and for counting the number of inequivalent structures, i.e., structures that have different bonding topologies. The most stable models are those that exhibit a honeycomb-chain structure at the step edge. One of our models (model ``f2'') reproduces the main features of the room temperature photoemission and scanning-tunneling microscopy data. Thus, we conclude that this model is a good candidate for the high temperature structure of the Si(553)-Au surface.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.