Characterization of the Ge(001)/Si-(2 x 1) surface using lattice dynamics

We present lattice dynamical calculations for segregated and nonsegregated models of the monolayer Si-covered Ge(001) surface. The calculations were p erformed using the adiabatic bend-charge model, with structural parameters and electronic charge distributions taken from recent ab initio pseudopoten tial calculations. We find that adsorption of Si results in several charact eristic phonon modes above the bulk continuum. These modes constitute a sig nature that may be used to distinguish between surface and subsurface Si ad sorbate layers. [S0163-1829(99)00840-1].