%0 Journal Article
%T Dynamics of Excited Electrons in Copper and Ferromagnetic Transition Metals: Theory and Experiment
%A R. Knorren
%A K. H. Bennemann
%A R. Burgermeister
%A M. Aeschlimann
%J Physics
%D 1999
%I arXiv
%R 10.1103/PhysRevB.61.9427
%X Both theoretical and experimental results for the dynamics of photoexcited electrons at surfaces of Cu and the ferromagnetic transition metals Fe, Co, and Ni are presented. A model for the dynamics of excited electrons is developed, which is based on the Boltzmann equation and includes effects of photoexcitation, electron-electron scattering, secondary electrons (cascade and Auger electrons), and transport of excited carriers out of the detection region. From this we determine the time-resolved two-photon photoemission (TR-2PPE). Thus a direct comparison of calculated relaxation times with experimental results by means of TR-2PPE becomes possible. The comparison indicates that the magnitudes of the spin-averaged relaxation time \tau and of the ratio \tau_\uparrow/\tau_\downarrow of majority and minority relaxation times for the different ferromagnetic transition metals result not only from density-of-states effects, but also from different Coulomb matrix elements M. Taking M_Fe > M_Cu > M_Ni = M_Co we get reasonable agreement with experiments.
%U http://arxiv.org/abs/cond-mat/9910326v2