A step from surface fiction towards surface science

The authors discuss the results of density-functional theory calculations on the adsorption of Na and K adatoms on Al(111). They describe the nature of the adsorbate-adsorbate and adsorbate-substrate interactions, and the mechanism of the formation of a periodic adlayer. The latter is shown to be actuated by surface vacancies and steps. They then discuss the formation energies of and the diffusion at steps, and they draw conclusions about the expected shape of adatom (and vacancy) islands and about crystal growth.