SURFACE VIBRATIONS AT CLEAN AND HYDROGENATED GAAS(11O) FROM AB-INITIO MOLECULAR-DYNAMICS

We present results of finite-temperature Car-Parrinello molecular dynamics simulations of the atomic geometry and the vibrations at clean and hydrogenated (1 and 0.25 ML coverages) GaAs(110) surfaces. Through an accurate analysis of the atomic motion based on signal processing techniques the phonon modes have been investigated. Some surface vibrational modes at high-symmetry k points, with layer-by-layer resolution of the eigenvectors, have been found. The results are compared with available experimental data and previous calculations.