Two reconstruction structures are proposed for Bi adsorption on Si(100) based on a first-principles local-density-functional molecular-cluster study employing total energies and atomic forces. Bi dimers, rather than monomers, are predicted to form the basic structure on the Si(100) surface. At high coverage, Bi adsorption leads to the breaking of Si dimers, which in turn removes the reconstruction of Si(100)2×1. Our results appear to explain recent results of scanning tunneling microscopy experiments.

• Received 7 March 1994

DOI:https://doi.org/10.1103/PhysRevB.50.1701