Ab initio calculation of the phonon dispersion of antimony-covered (110) surfaces of III-V compounds

We present the results from nh initio linear-response calculations performed to investigate the surface phonon dispersion of the antimony-covered (110) surfaces of GaAs, GaP, InAs, and InP. Our computations are carried out for a complete monolayer coverage of antimony adsorbed in the epitaxial continued layer structure. The surfaces are described within the slab-supercell approach. Our density-functional formalism is based on the plane-wave pseudopotential method and the local-density approximation. Rie identify characteristic vibrations of the adsorption overlayer, interface modes, and phonons related to those of the pristine surfaces with changed dispersion due to the adsorption. A comparison of the modes computed for the different systems allows us to analyze systematic trends and to study more thoroughly the physical origin of vibrational states occurring on adsorbate-covered and clean III-V(110) surfaces. Our computed phonon frequencies are in good agreement with experimental data.