Spatial variation of the surface state onset close to three types of surface steps on Ag(111) studied by scanning tunnelling spectroscopy

Abstract

A regular step, a dislocation slip step and a step formed by the emergence of a split edge dislocation (SED) to the surface influence the local density of states close to the onset of the surface state as investigated by scanning tunnelling spectroscopy at low temperature.The onset of the surface state shifts close to the regular step and the dislocation slip step by approximately 15 meV towards the Fermi energy.Additional maxima above the onset are only observed if a second step leads to confinement.In both cases, the conductivity decreases close to the step.However, an increase in conductance above the surface state onset is observed close to the SED step.Furthermore, a variety of additional states are discernable.Thus, different types of steps lead to markedly different changes in the local electronic structure on surfaces.© IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.