Berlin 2012 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 23: Magnetization / Demagnetization Dynamics II
MA 23.9: Vortrag
Mittwoch, 28. März 2012, 12:00–12:15, H 1012
Towards atomistic tight-binding spin dynamics — •S. Rossen1,2, P. Mavropoulos1, T. Schena1, S. Blügel1, and Th. Rasing2 — 1Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA, 52425 Jülich, Germany — 2Institute for Molecules and Materials, Radboud Universiteit Nijmegen, 6525 AJ Nijmegen, The Netherlands
This work is motivated by the increasing interest in atomistic magnetization dynamics [1]. Until now, the computational approaches are mainly based on model Hamiltonians of the magnetic system. Here we will present a method based on the adiabatic approximation in which the electronic structure is recalculated within the tight-binding approximation during the time evolution, so that the transverse and longitudinal magnetic as well as charge degrees of freedom are coupled [2]. The torques acting on the magnetic moments are obtained self-consistently using constraining fields [3]. It is then possible to describe the magnetization dynamics of a strongly non-equilibrium magnetic state. We will show model calculations of such dynamics where we mainly focus on the integration of the Landau-Lifshitz equation with torques calculated by means of the tight-binding method. The presented results are compared with those of a classical Heisenberg model.
[1] A. Kirilyuk et al., Rev. Mod. Phys. 82, 2731 (2010).
[2] V. P. Antropov et al., Phys. Rev. B 54, 1019 (1996).
[3] L. M. Small and V. Heine, J. Phys. F: Met. Phys. 14, 3041 (1984).