Surface phonons on Si(0 0 1)/As(2×1)

Abstract

We present results of phonon calculations for the Si(0 0 1)/As(2×1) surface using the adiabatic bond-charge model. It is found that this surface is characterized by two pronounced peaks in the phonon density of states. One of these lies below the bulk continuum at the zone edges and is due to surface acoustic waves involving vibrations of the As atoms. The second of these lies at the bulk acoustic-optical boundary and is related to the vibrations of the symmetric As–As dimer against the substrate.