Observation of a possible surface-charge-density oscillation by the adsorption of an impurity.

Abstract

Neon field-ion image spots of impurities deposited from a Ta wire source on the Ir(100) surface show a halo-ring structure. Using an atom-probe field-ion microscope, these impurities are tentatively identified as tantalum hydrides. This halo-ring image-spot structure is most probably produced by the perturbation of the electronic charge-density distribution of the substrate around the impurity by its adsorption.