Density-functional calculation of phonons in adsorbate-covered semiconductor surfaces

We present the results from density-functional calculations of the phonon d ispersion of adsorbate-covered semiconductor surfaces. The plane-wave metho d is used together with the slab-supercell description for the surfaces. We focus on vibrational states that characterize the chemisorption site of th e adsorbed atoms and phonon modes of the interface. By comparing the vibrat ional states in the presence of the adsorbates with those of the clean surf aces, adsorption-induced changes of the surface geometry and force constant s can be identified. We study the chemisorption of hydrogen, antimony, and group-III elements on the (110) surfaces of III-V compounds, as well as on the (001) and (111) surfaces of silicon. (C) 1999 Elsevier Science B.V. All rights reserved.