title: Ultrafast electron dynamics at metal interfaces: intraband relaxation of image state electrons as friction.
abstract: Two-photon photoemission of image potential states above monolayers of p-xylene/Ag(111) shows that electrons with different momenta have very different rise and decay rates as a function of parallel momentum. The dynamics are due to energy and momentum loss (intraband relaxation), which we model as a stochastic process isomorphic to the overdamped motion of a harmonic oscillator. The method extracts a friction coefficient from the data which can be explained by electron-electron scattering in a formalism based on the Lindhard dielectric function. One-electron excitations (interband transistions) dominate the dissipation mechanism, with a smaller contribution from collective electronic excitations (plasmons).
authors.affiliation: Chemistry Department, University of California-Berkeley, Berkeley, CA 94720, USA.
authors.forename: Sean
authors.initials: S
authors.lastname: Garrett-Roe
authors.forename: Steven T
authors.initials: ST
authors.lastname: Shipman
authors.forename: Paul
authors.initials: P
authors.lastname: Szymanski
authors.forename: Matthew L
authors.initials: ML
authors.lastname: Strader
authors.forename: Aram
authors.initials: A
authors.lastname: Yang
authors.forename: Charles B
authors.initials: CB
authors.lastname: Harris