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

Abstract

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