Dynamics of Excited Electrons in Copper and Ferromagnetic Transition Metals: Theory and Experiment
Abstract
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.
Keywords
Cite
@article{arxiv.cond-mat/9910326,
title = {Dynamics of Excited Electrons in Copper and Ferromagnetic Transition Metals: Theory and Experiment},
author = {R. Knorren and K. H. Bennemann and R. Burgermeister and M. Aeschlimann},
journal= {arXiv preprint arXiv:cond-mat/9910326},
year = {2009}
}
Comments
23 pages, 11 figures, added a figure and an appendix, updated references