Adsorption of Fe on GaAs(100) Surface

The adsorption of one monolayer Fe atoms on an ideal GaAs (100) surface is studied by using the self-consistent tight-binding linear muffin-tin orbital method. The Fe adatom chemisorption on Ga- and As-terminatedsurface are considered separately. A monolayer of S atoms is used to saturate the dangling bonds on one of the supercellsurfaces. Energies of adsorption systems of an Fe atom on different sites are calculated, and the charge transfers areinvestigated. It is found that Fe-As interaction is stronger than Fe-Ga interaction and Fe atoms prefer to be adsorbed onthe As-terminated surface. It is possible for the adsorbed Fe atoms to sit below the As-terminated surface resulting inan Fe-Ga-As mixed layer. The layer projected density states are calculated and compared with that of the clean surface.