Low-temperature scanning tunneling spectroscopy of magnetic and non-magnetic metal atoms on Ag(111) and on Cu(111) surfaces reveals the existence of a common electronic resonance at an energy below the binding energies of the surface states. Using an extended Newns-Anderson model, we assign this resonance to an adsorbate-induced bound state, split off from the bottom of the surface-state band, and broadened by the interaction with bulk states. A lineshape analysis of the bound state indicates that native adatoms decrease the surface-state lifetime, while a cobalt adatom causes no significant change.
@article{arxiv.cond-mat/0405397,
title = {Surface-State Localization at Adatoms},
author = {L. Limot and E. Pehlke and J. Kroeger and R. Berndt},
journal= {arXiv preprint arXiv:cond-mat/0405397},
year = {2009}
}