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TT: Tiefe Temperaturen

TT 30: Postersitzung IV: Kritische Ph
änomene, Quantenstörstellen, niederdimensionale Systeme

TT 30.34: Poster

Thursday, March 11, 2004, 14:30–19:00, Poster A

Electron Mass Enhancement on the Spin Wave Energy Scale — •Jörg Schäfer, David Schrupp, and Ralph Claessen — Institut für Physik, Universität Augsburg, 86135 Augsburg

High-resolution photoelectron spectroscopy is used to explore metallic states localized at the Fe(110) surface which provide an opportunity to study quasiparticle renormalization effects in a magnetic system. Modifications from a conventional parabolic dispersion are observed up to rather high binding energies, exceeding the phonon energy scale by an order of magnitude. Analysis of the spectral function in terms of the real and imaginary part of the self energy yield the typical signature of coupling of the electrons to an excitation spectrum. The characteristic energy scale of ∼ 160 meV is in striking agreement with spin waves detected by neutron scattering and therefore points at electron-magnon coupling. Comparison to spin wave dispersions and related features in electron energy loss spectra is made. A model for spin-wave-induced quasiparticle renormalization which describes the spectroscopic behavior of the data is presented.