Title: Phonon-Driven Orbital Transport via Surface Acoustic Waves
When: Monday, February 26, 2026, 12:00
Place: Department of Theoretical Condensed Matter Physics, Faculty of Sciences, Module 3, Seminar Room (5th Floor)
Speaker: Marc Rovirola, Universidad de Barcelona
Electrons do not carry only charge and spin, but also orbital angular momentum, which can provide an extra degree of freedom for information transport. Recently, it has been shown that orbital currents can propagate even in materials with weak spin-orbit coupling, giving access to a wider range of materials than its spin counterpart. However, its coherent generation and detection remain largely unexplored. Our recent experiments demonstrate phonon-induced generation of orbital currents in ferromagnetic (FM)/non-magnetic (NM) heterostructures driven by surface acoustic waves (SAW). Surface acoustic waves (SAWs) exhibit an intrinsic elliptical particle motion that carries a local rotation of the lattice. This rotation can directly couple to the electronic orbital degree of freedom, enabling the generation of orbital currents in adjacent metallic layers without electrical injection. We demonstrate that these phonon-driven orbital currents interact strongly with neighboring ferromagnets and can be detected electrically through orbital-to-charge conversion. By comparing different material combinations, we identify clear signatures of orbital transport and show that acoustic excitation can outperform conventional electrical methods. These results highlight SAWs as an efficient platform for phononic control of orbital angular momentum. [1] M. Rovirola et al., arXiv:2512.08385 (2025)
