The ordering of Bi on a Si(111)-7×7 surface was studied as a function of overlayer coverage and deposition conditions using low-energy-electron diffraction (LEED) and Auger electron spectroscopy. We observed a one-third-monolayer and a saturated one-monolayer phase. Both phases displayed identical √3 × √3- R30° LEED symmetries. LEED intensity data were used to differentiate between the two phases and to determine a quantitative atomic geometry via a thorough dynamical LEED analysis.

• Received 19 April 1991

DOI:https://doi.org/10.1103/PhysRevB.44.3471