Münster 1999 – wissenschaftliches Programm

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AM: Magnetismus

AM 10: Postersitzung

AM 10.28: Poster

Dienstag, 23. März 1999, 16:15–20:00, F\"urstenberghaus

Temperature dependent electronic structure of EuO films — •W. Müller, R. Schiller, and W. Nolting — Humboldt Universität zu Berlin

We investigate the temperature dependent quasiparticle spectrum of a ferromagnetic semiconducting film within the framework of the sf-model. Exact results are derived for the special case of a single itinerant electron being exchange coupled to a ferromagnetically saturated localised spin system (EuO, EuS) [1]. Starting from that exactly solvable case we introduce the temperature via the temperature and layer-dependent magnetisations of the f-spins calculated in the Random Phase Approximation (RPA)[3]. We assume a simple cubic film cut parallel to the (100) crystal plane. The mutual influence of correlation effects and the reduced symmetry of the film is worked out by inspecting spectral densities and local quasiparticle densities of states. It is shown that the variation of the hopping integrals in the vicinity of the surface leads to the existence of surface states [2]. The temperature dependence of the surface states is investigated.
[1] R. Schiller, W. Müller, W. Nolting, J. Magn. Magn. Mater., 169, 39 (1997)
[2] R. Schiller, W. Müller, W. Nolting, Europ. Phys. J. B, 2, 249 (1998)
[3] R. Schiller, W. Nolting, submitted to Solid State Com.