Inter- and intraband inelastic scattering of hot surface state electrons at the Ag(111) surface

The phase coherence length and the corresponding lifetime of hot electrons in the surface state band of Ag(1 1 1) have been measured with a low temperature STM for energies from the Fermi level to 3 eV. A divergence of the lifetime from a (E - E-F)(-2) behavior has been observed for energies lower than 400 meV. Theoretical analysis in terms of electron-electron and electron-phonon scattering mechanisms shows that the energy dependence of the lifetime is accounted for by the competition between intra- and interband electron-electron inelastic scattering and electron-phonon contributions. (C) 2002 Elsevier Science B.V. All rights reserved.