Direct measurements of the L-gap surface states on the (111) face of noblemetals by photoelectron spectroscopy - art. no. 115415

We present a comprehensive photoemission study of the L-gap surface states of the (111) surfaces of Cu, Ag, and Au by high-resolution angle-resolved p hotoelectron spectroscopy (PES). With an angular resolution of about Delta theta = +/-0.15 degrees and an energy resolution of DeltaE approximate to3. 5 meV, our data establish new values for the intrinsic lifetime broadening and the dispersion relation of these surface states. We compare our photoem ission results to recently published theoretical calculations and measureme nts by scanning tunneling spectroscopy (STS). In the case of the Au(111) st ate, we observe particular qualitative discrepancies in comparison to the S TS data: the PES data show a split dispersion and Fermi surface, possibly c aused by a spin-orbit interaction of the surface state electrons.