Dresden 2020 – wissenschaftliches Programm
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SYAS 1.2: Hauptvortrag
Montag, 16. März 2020, 15:30–16:00, HSZ 02
Ab-initio treatment of ultrafast spin-dynamics — •Sangeeta Sharma1 and J. K. Dewhurst2 — 1Max-Born Institute for Nonlinear Optics and Short Pulse Spectroscopy, Max-Born-Strasse 2A, 12489 Berlin, Germany — 2Max planck Inst. Halle, Weinberg 2, 06120 Halle
I will talk about all-optical switching of long-range magnetic order. The type of coupling between the constituent atoms of a magnetic solid, usually ferromagnetic (FM) or anti-ferromagnetic (AFM), is a fundamental property of any magnetic material. This coupling is governed by the exchange interaction, for which the time scale of a typical magnetic material is of the order of a few 100s of femtoseconds. In our work, using time-dependent density functional theory (TDDFT), we demonstrate that a rich control over magnetization at sub-exchange time scales (of the order of few tens of femtoseconds) is possible[1,2,3,4]. This even includes changing the magnetic order from AFM to FM. By investigating a wide range of multi-sublattice magnetic materials we are able to formulate three simple rules that predict the qualitative dynamics of magnetization for ferromagnetic, anti-ferromagnetic, and ferri-magnetic materials on sub-exchange time scales.
 Shokeen et al. Phys. Rev. Lett. 119, 107203 (2017)  Elliott et al. Scientific Reports 6, 38911 (2016)  Chen et al. Phys. Rev. Lett. 122, 067202 (2019)  Siegrist et al. Nature 571, 240 (2019)  Dewhurst et al. Nano Lett. 18, 1842, (2018)