SKM 2023 – scientific programme

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MA: Fachverband Magnetismus

MA 8: Ultrafast Magnetization Effects I

MA 8.8: Talk

Monday, March 27, 2023, 17:00–17:15, HSZ 04

A real-space tight-binding approach to ultrafast spin dynamics in inhomogeneous systems — •Franziska Ziolkowski, Oliver Busch, Ingrid Mertig, and Jürgen Henk — Martin Luther University Halle-Wittenberg, Halle, Germany

In laser-induced ultrafast spin dynamics a spin current is generated at a magnetic-nonmagnetic interface, whose orgin and properties are still under debate. To better understand the microscopic processes and the role of the interface we are developing the theoretical framework evolve [1].

In a real-space tight-binding model the electron system is optically excited by a femtosecond laser pulse and coupled to a bosonic bath. The time evolution of the density operator yields occupation numbers, demagnetization profiles as well as spin- and orbital-resolved occupation flows.

Our simulations confirm the importance of interfaces for ultrafast transport phenomena and demagnetization processes. We identify a reflow from Cu d orbitals across the interface into Co d orbitals as an important contribution to demagnetization. This refilling manifests itself as a minority-spin current proceeding several layers into the Cu region.

Moreover, we investigate the influence of pulse parameters such as polarization and photon energy.

[1] Töpler et al 2021 New J. Phys. 23 033042