Many-Body Interactions And Rashba Splitting Of The Surface State On Cu(110)

Using high-resolution angle-resolved photoemission spectroscopy, we elucidate the Rashba splitting of Delta k(F) = 0.003 angstrom(-1) near the Fermi level (E-F) in the Shockley surface state of Cu(110) at the (Y) over bar point of the surface Brillouin zone. The observed energy-band dispersion exhibits a kink structure at similar to-20 meV, which is a clear indication of band renormalization caused by an electron-phonon interaction. The electron-phonon coupling parameter is found to be lambda(ep) = 0.17 +/- 0.02 based on the experimentally obtained real part of the self-energy. First-principle calculations yield lambda(ep) = 0.160 and Delta k(F) = 0.004 angstrom(-1) at E-F, which are fully consistent with the experimental results. In addition, the contributions of the electron-electron and electron-phonon interactions to the linewidth of the surface state at the Y point are experimentally determined to be Gamma(ee) similar to 9 meV and Gamma(ep) similar to 7 meV, respectively. We demonstrate that the Rashba splitting must be resolved by photoemission line-shape analysis for an accurate determination of the electron self-energy and coupling parameters.