Berlin 2024 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
MA: Fachverband Magnetismus
MA 24: Terahertz Spintronics I
MA 24.6: Vortrag
Mittwoch, 20. März 2024, 10:45–11:00, EB 202
Terahertz spin transport and spin charge conversion dynamics in topological-insulator|ferromagnet heterostructures — •Genaro Bierhance1,2, Chihun In2, Enzo Rongione3,4, Reza Rouzegar2, Oliver Gueckstock2, Emanuele Longo5,6, Tom Sebastian Seifert2, Roberto Mantovan5, Henri Jaffrès3, Athanasios Dimoulas7, and Tobias Kampfrath1,2 — 1FHI Berlin, Germany — 2FU Berlin, Germany — 3CNRS, Paris, France — 4ICN2, Barcelona, Spain — 5CNR-IMM, Italy — 6ICMAB, Barcelona, Spain — 7NCSRD, Athens, Greece
Topological insulators are promising materials for terahertz (THz) spintronic devices due to their topologically protected surface states with spin-momentum locking, which unveil channels for spin-charge interconversion (SCI). Here, we study ultrafast spin transport and SCI in F|TI stacks consisting of a ferromagnetic metal layer (F) and a topological-insulator film (TI). An incident femtosecond laser pulse induces a spin voltage and, thus, spin transport from F to TI. Subsequent SCI launches a transverse charge current that emits a broadband THz electromagnetic pulse. A detailed analysis of the obtained THz emission signal dynamics in the TI Bi2Te3 reveals two relaxation components with distinct time scales: a quasi-instantaneous and a significantly longer response. Remarkably, the extracted time constant (300 fs) of the latter is independent of the chosen F material (Fe or Co). We ascribe these observations to a slower response of either spin transport or SCI in Bi2Te3, indicating the importance of intermediate states in these structures.
Keywords: terahertz; spintronics; topological insulators; ultrafast spin transport; spin charge current interconversion