First-principles study of structural and dynamical properties of As overlayers on InP(1 1 0)

A first-principles study, using a linear-response approach based on the pseudopotential method and the local density functional scheme, has been carried out for the structural and dynamical properties of As overlayers on InP(1 1 0). Computations have been performed for two structural models: epitaxially continued layer structure and an exchange-reacted structure. For both structural models, we find several characteristic phonon modes in the bulk acoustic-optical gap region. These results have allowed us to provide a critical assessment of the previously reported dynamical properties of this system obtained from the application of a bond charge model.