Femtosecond time-resolved two-photon photoemission studies of electron dynamics in metals

http://dipc.ehu.es/Echenique/index.htm/admin/documentos/archivos/publicaciones/186SS1999.pdf

Image potential states on metal surfaces: binding energies and wave functions

Electron dynamics in the bulk and at the surface of solid materials are well known to play a key role in a variety of physical and chemical phenomena. In this article we describe the main aspects of the interaction of low-energy electrons with solids, and report extensive calculations of inelastic lifetimes of both low-energy electrons in bulk materials and image-potential states at metal surfaces. New calculations of inelastic lifetimes in a homogeneous electron gas are presented, by using various well-known representations of the electronic response of the medium. Band-structure calculations, which have been recently carried out by the authors and collaborators, are reviewed, and future work is addressed.

/pdf/theory-of-inelastic-lifetimes-of-low-energy-electrons-in-18p3bz565y.pdf

Theory of inelastic lifetimes of low-energy electrons in metals

Electron dynamics at surfaces

▪ Abstract Two-photon photoemission is a promising new technique that has been developed for the study of electron dynamics at interfaces. A femtosecond laser is used to both create an excited electronic distribution at the surface and eject the distribution for subsequent energy analysis. Time- and momentum-resolved two-photon photoemission spectra as a function of layer thickness fully determine the conduction band dynamics at the interface. Earlier clean surface studies showed how excited electron lifetimes are affected by the crystal band structure and vacuum image potential. Recent studies of various insulator/metal interfaces show that the dynamics of excess electrons are largely determined by the electron affinity of the adsorbate. In general, electron dynamics at the interface are influenced by the substrate and adlayer band structures, dielectric screening, and polaron formation in the two-dimensional overlayer lattice.

http://www.cchem.berkeley.edu/cbhgrp/papers/711.pdf

D.F. Padowitz

Papers

Electrons at metal-insulator interfaces : I. The effect of Xe monolayers on the image potential states of Ag(111)