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MA: Fachverband Magnetismus

MA 55: Poster II

MA 55.85: Poster

Freitag, 4. April 2014, 10:30–13:30, P2

Adiabatic and dynamic spin-wave spectra in the homogeneous electron gas — •Maximilian Kulke and Arno Schindlmayr — Department Physik, Universität Paderborn, 33095 Paderborn, Germany

Spin-wave spectra of itinerant ferromagnets can be calculated from a variety of ab initio methods, such as the adiabatic frozen-magnon approximation, time-dependent density-functional theory or many-body perturbation theory. A quantitative comparison for real materials is not straightforward, however, because practical implementations of these schemes typically rely on different numerical approximations. To avoid such difficulties and allow a clearer assessment, we study spin waves in the spin-polarized homogeneous electron gas, where an almost completely analytic evaluation of these methods is possible. Within the adiabatic approximation we seek self-consistent solutions of the static Kohn-Sham equations with a constraint that enforces a noncollinear spin-spiral configuration with a given wave vector. As an alternative, we obtain the spin-wave dispersion from the poles of the dynamic transverse spin susceptibility within time-dependent density-functional theory. The same exchange-correlation functional, the (adiabatic) local-spin-density approximation, is used in both cases. Besides a comparison of the calculated spin-wave energies over a large range of wave vectors, we specifically focus on the spin-wave stiffness, which corresponds to the leading parabolic dispersion coefficient in the limit of long wave lengths.