title: Dynamics of the self-energy of the Gd(0001) surface state probed by femtosecond photoemission spectroscopy.
abstract: Transient changes of the complex self-energy of the 5d(z2) surface state on Gd(0001) after intense optical excitation are investigated by femtosecond time-resolved photoemission. We observe an ultrafast (<100 fs) broadening of the linewidth due to e-e scattering followed by a decrease of the binding energy due to thermal expansion of the lattice. In addition, we resolve a periodic breathing of the band structure which originates from a coherent phonon. An amplitude of 1 pm is derived from the binding energy shift upon lattice displacement calculated by density functional theory.
authors.affiliation: Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin-Dahlem, Germany.
authors.forename: P A
authors.initials: PA
authors.lastname: Loukakos
authors.forename: M
authors.initials: M
authors.lastname: Lisowski
authors.forename: G
authors.initials: G
authors.lastname: Bihlmayer
authors.forename: S
authors.initials: S
authors.lastname: Blügel
authors.forename: M
authors.initials: M
authors.lastname: Wolf
authors.forename: U
authors.initials: U
authors.lastname: Bovensiepen