Dynamical properties of Sb- and Bi-covered (110) surfaces of III-V compounds

We present results from plane-wave pseudopotential calculations and density-functional perturbation theory applied to investigate the surface phonon dispersion of (110) surfaces of InAs and InP covered by monolayers of Sb and Bi. The importance of vibrational spectroscopy for the investigation of structural properties is demonstrated for the Bi-covered InAs(110) surface which forms a (1×1) and, in addition, a (1×2) phase. Our calculations predict two prominent low-frequency modes which are fingerprints of the missing-row reconstruction recently proposed for the (1×2) phase. A comparison of the modes allows us to analyse systematic trends and to study the physical origin of vibrational states occurring on clean and adsorbate-covered Owen(underscore)Haskins(at)espicom.comIII-V(110) surfaces. The electronic band structure computed for the (1×1) and (1×2) phases of the Bi-covered InAs(110) surface is in agreement with experimental data. Compared with the (1×1) phase, we find a much smaller band gap for the (1×2) reconstruction.