PHONONS AT III-V (110) SURFACES

We have applied the ab initio pseudopotential frozen phonon approach t o study phonon frequencies and eigenmodes for III-V (110) surfaces. Fo r GaAs our results at the <(Gamma)over bar> and (X) over bar points ar e in good agreement with data from recent HREELS and He scattering exp eriments. In the energy range of the controversially discussed A(1) mo de we observe a rotational surface phonon with substantial bulk contri butions. Calculations for surface <(Gamma)over bar> phonons of InAs, G aP and InP show that energy shifts and displacement patterns are stron gly correlated with constituent atomic masses.