Decay mechanisms of single particle excitations in bulk metals and at surfaces

Eugene Chulkov

Facultad de Ciencias Quimicas, Departamento de Fisica de Materiales, University of the Basque Country,
Donostia International Physics Center, Apdo.1072, 20080 San Sebastian/Donostia, Spain

Recent theoretical work on the excited electron and hole dynamics in bulk metals and at surfaces is reviewed. Inelastic electron-electron and electron-phonon contributions to the quasiparticle lifetimes are discussed in terms of different decay mechanisms: the creation of electron-hole pairs, charge density (plasmon) excitaions, spin-density (magnon) excitations, and excitation of phonons. The role of screening in the quasiparticle decay is also analysed. Quasiparticle self-energy is calculated within GW and/or GW + T-matrix approximations. Exaples are given for intrinsic surface states, image-potential and quantum well states, as well as for bulk states.