Dresden 2009 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 5: Electron Theory of Magnetism

MA 5.8: Vortrag

Montag, 23. März 2009, 12:45–13:00, HSZ 103

Spin-wave excitations from time-dependent density-functional theory — Manfred Niesert¹, Arno Schindlmayr², Christoph Friedrich¹, and •Stefan Blügel¹ — ¹Institut für Festkörperforschung & Institute for Advanced Simulation, Forschungszentrum Jülich, 52425 Jülich — ²Department Physik, Universität Paderborn, 33098 Paderborn

Spin waves constitute an important class of low-energy excitations in magnetic solids with a characteristic material-specific dispersion and a direct relation to magnetization dynamics. Until now most theoretical studies were based on the Heisenberg model of localized spins or on the frozen-magnon method, but neither is applicable to investigate the dynamics of spin waves in metallic systems with itinerant electrons. As a possible solution, time-dependent density-functional theory gives access to the full frequency-dependent transverse spin susceptibility, from which not only the spin-wave dispersion but also the corresponding excitation lifetimes and other spectral information can be extracted. We have developed a practical scheme to calculate spin-wave spectra from first principles within this framework and present results for the prototype transition metals Iron, Cobalt and Nickel. Our implementation uses the full-potential linearized augmented plane-wave (FLAPW) method, and dynamic exchange-correlation effects are in the first instance described by the adiabatic local-density approximation.