LEED studies of lead on copper (100)
Lead layers on copper (100) at coverages from 0.5 to 0.6 were investigated by quantitative LEED and AES measurements and dynamical LEED calculations. Comparisons of intensity measurements with dynamical calculations for the (Wurzel2 x Wurzel2)R45\xb0 structure show that the Pb atoms are adsorbed in hollow sites. The Cu---Pb distance is close to the sum of both metallic radii. The dense lead monolayer at a coverage of 0.6 exhibits a c(5 Wurzel2 x Wurzel2)R45\xb0 superstructure with cmm symmetry of the diffraction pattern. Calculations for five models were performed under variation of several geometric parameters. Most analogies were found for regular arrangements of distorted (Wurzel2 x Wurzel2)R45\xb0 domains, separated by antiphase boundaries. This result is in consistency with observations of poorly ordered (Wurzel2 x Wurzel2)R45\xb0 antiphase domains at intermediate coverages.