A theoretical study for the influence of coverage on Li, Na and K adsorption on Co(0Â 0Â 0Â 1)

Periodic density-functional theory calculations of Li, Na and K adsorbed on Co(0 0 0 1) have been performed up to the coverage of 0.5 ML. Calculated results indicate that top, bridge and hollow sites are degenerated with almost identical adsorption energies for all considered cases. The adsorption energies, optimized structures, work function and electron charge density changes are discussed. We have also studied the possibility of substitutional adsorption and the results are compared with that on-surface adsorption, in particular for the p(2 × 2) overlayer.