SPICE Workshop on Spin textures: Magnetism meets Plasmonics, July 23rd - 25th 2024
Ingrid Mertig
Oliver Busch1, Franziska Ziolkowski1, Börge Göbel1, Jürgen Henk1, and Ingrid Mertig1
1Institute of Physics, Martin Luther University Halle-Wittenberg, 06099 Halle, Germany
Email: ingrid.mertig@physik.uni-halle.de
An orbital current can be generated whenever an object has a translational and rotational degree of freedom. In condensed matter physics, intra-atomic contributions to the transverse orbital transport, labeled orbital Hall effect [1, 2], rely on propagating wave packets that must consist of hybridized atomic orbitals. However, inter-atomic contributions [3] are equally important as they give rise to a new mechanism for generating orbital currents [4]. It is shown, that even wave packets consisting purely of s electrons can transport orbital angular momentum if they move on cycloidal trajectories.
Furtheron, it will be shown, that the orbital Hall effect in a metal can be extended into the femtosecond time domain [5]. We investigate theoretically orbital angular momenta and their currents induced by a femtosecond laser pulse in a Cu nanoribbon. Our numerical simulations provide detailed insights into the laser-driven electron dynamics on ultrashort timescales with atomic resolution. The ultrafast orbital Hall effect established in this work complies with the familiar pictorial representation of the static orbital Hall effect, but we find also pronounced differences between physical quantities that carry orbital angular momentum and those that do not. This study lays the foundations for investigations of ultrafast Hall effects in confined
metallic systems.
References
[1] Y. Cao, G. Xing, H. Lin, N. Zhang, H. Zheng, and K. Wang, iScience 23, 101614 (2020).
[2] D. Go, D. Jo, H.-W. Lee, M. Kläui, and Y. Mokrousov, Europhys. Lett. 135, 37001 (2021).
[3] T. Yoda, T. Yokoyama, and S. Murakami, Nano Letters 18, 916 (2018).
[4] Oliver Busch, Börge Göbel, and Ingrid Mertig, Phys. Rev. B 108, 184401 (2023).
[5] Oliver Busch, Franziska Ziolkowski, Ingrid Mertig, and Jürgen Henk, Phys. Rev. Research 6, 013208 (2024).