Local and non-local spin-dependent ultrafast electronic current dynamics in ferromagnetic heterostructures

• Applicant: Professor Dr. Uwe Bovensiepen
• Subject Area: Experimental Condensed Matter Physics
• Term: since 2026
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 572793420

Analysis of microscopic spin-dependent interaction processes is a fundamental challenge in solid-state physics with immediate implications to applications in devices. Time-resolved photoelectron spectroscopy with spin resolution is the preferred method to provide such insights due to its built-in energy and momentum sensitivity. This method was applied to problems of ultrafast spin dynamics already earlier. The analysis of spin dynamics in transport phenomena with energy and momentum resolution remains, however, to be established. In this proposal we take up the challenge to address spin-dependent scattering in transport processes of hot electrons in metallic heterostructures that have become already useful devices for THz generation due to the inverse spin Hall effect. This effort becomes particularly promising since it joins forces of spin-resolved ARPES located in Hiroshima, Japan, and expertise in the analysis of electron transport available in Duisburg, Germany. In detail, we will use femtosecond time- and spin-resolved photoelectron emission spectroscopy on Au/Fe/MgO(001) and Ru/Fe/MgO(001) heterostructures to (i) analyze the spin-dependent hot electron lifetimes in these heterostructures, (ii) study the spin-dependent transport regime in non-equilibrium based on the propagation times, and (iii) develop, on this basis, angle-resolved experiments to measure the inverse spin Hall effect as a function of electron energy.

• DFG Programme: Research Grants
• International Connection: Japan
• Partner Organisation: Japan Society for the Promotion of Science (JSPS)
• Cooperation Partner: Professor Dr. Kenta Kuroda