Benjamin Jungfleisch
Three-dimensional topological insulators with large spin Hall conductivity have emerged as potential candidates for efficient spintronic applications. Here, we report spin-to-charge conversion in ferromagnet (Fe78Ga13B9 and Fe75Co25) – three-dimensional topological insulator (Bi85Sb15 and Bi2Te3) heterostructures [1,2]. We address the spin-to-charge conversion process at complementary time scales through (1) ferromagnetic resonance induced spin pumping and inverse spin Hall effect (ISHE) and (2) femtosecond laser-induced spin-current generation and ultrafast spin-to-charge conversion by ISHE leading to THz charge transients [3]. The spin pumping parameters derived from the measurements of the femtosecond light-pulse-induced terahertz emission are consistent with the results of ferromagnetic resonance and in remarkable agreement with theoretical modeling results. Our results show that ferromagnet/topological insulator interfaces are promising for creating novel spin-orbit torque devices at GHz and THz frequencies.
Research at Delaware supported by NSF through the University of Delaware Materials Research Science and Engineering Center, DMR- 2011824. Research at Morgan State supported by the Air Force Office of Scientific Research through Grant No. FA9550-19-1-0082.
References:
[1] Sharma et al., Phys. Rev. Materials 5, 124410 (2021)
[2] Sharma et al., Appl. Phys. Lett. 122, 072403 (2023)
[3] Wu et al., J. Appl. Phys. 130, 091101 (2021)