Berlin 2008 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 30: Electron Theory

MA 30.9: Vortrag

Donnerstag, 28. Februar 2008, 16:45–17:00, H 1028

Spin-wave excitations from time-dependent density-functional theory — •Manfred Niesert, Arno Schindlmayr, Christoph Friedrich, and Stefan Blügel — Institut für Festkörperforschung, Forschungszentrum Jülich, 52425 Jülich, Germany

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 illustrate its performance by applications to prototype ferromagnetic transition metals. Our implementation uses the full-potential linearized augmented plane-wave method, and dynamic exchange-correlation effects are in the first instance described by the adiabatic local-density approximation.