Dresden 2026 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 38: Ultrafast Magnetization Effects II

MA 38.5: Vortrag

Mittwoch, 11. März 2026, 16:00–16:15, POT/0361

Light-induced ultrafast magnetization dynamics driven by chiral phonons — •Shiqi Hu and Sangeeta Sharma — Max-Born Institute for Nonlinear Optics and Short Pulse Spectroscopy,Berlin,Germany

The pursuit of high-speed, low-power information processing is driving advanced research into ultrafast laser control of magnetic order. Going beyond conventional approaches that rely on heterojunctions for spin-current injection, this work demonstrates direct manipulation of magnetism in bulk materials through intrinsic interactions. Using circularly polarized laser excitation, we generate THz chiral phonons in the non-collinear antiferromagnet Mn3Sn with a Kagome lattice. The angular momentum of these phonons produces an effective magnetic field, inducing coupled in-plane and out-of-plane spin precession that reorients the magnetic octupole. This reorientation, in turn, modulates the topological properties of Weyl points. Spin*orbit coupling and the rotational motion of chiral phonons are shown to be essential to this mechanism. We attribute the observed spin dynamics to a competition between the phonon-induced effective field*favoring ferromagnetic alignment*and the intrinsic antiferromagnetic spin interactions in the Kagome lattice. These findings open a new pathway for controlling magnetic topology.

Keywords: ultrafast magnetism; non-collinear antiferromagnet; chiral phonon; laser control