| AVS 64th International Symposium & Exhibition | |
| Magnetic Interfaces and Nanostructures Division | Tuesday Sessions |
| Session MI+2D+AC+NS-TuA |
| Session: | Spin-Orbit Phenomena at Surfaces and Interfaces |
| Presenter: | Axel Hoffmann, Argonne National Laboratory |
| Authors: | M.B. Jungfleisch, Argonne National Laboratory Q. Zhang, Argonne National Laboratory W. Zhang, Oakland University J.E. Pearson, Argonne National Laboratory H. Wen, Argonne National Laboratory A. Hoffmann, Argonne National Laboratory |
| Correspondent: | Click to Email |
Electromagnetic terahertz (THz) radiation is a versatile tool for a wide variety of sensing technologies ranging from security systems to medical applications. Commonly THz radiation is generated using semiconducting materials and using their inherent charge dynamics. Recently, it was also demonstrated that optical excitation of fast spin current pulses in magnetic materials may generate strong broadband THz radiation from transverse spin transport phenomena, known as spin Hall effects. These experiments rely on a bulk conversion of spin currents into charge current, which then subsequently generate the THz radiation. Here we investigate whether interfacial spin-orbit coupling phenomena may also be an efficient source for generating THz radiation. For this purpose we combine a bilayer of Ag and Bi, which is known to have strong Rashba-type spin-orbit coupling at its interface with a magnetic CoFeB layer. Upon optical excitation we also observe in this system THz radiation. Additional experiments with individual Ag and Bi layers show that this radiation originates from interfacial spin galvanic effects. Furthermore, we demonstrate that the amplitude of the THz radiation varies with the helicity of the incident optical light pulse. These observations open up new perspectives for the development of ultrafast spintronic devices.
This work was supported by the U.S. Department of Energy, Office of Science, Materials Sciences and Engineering Division. Lithographic patterning was carried out at the Center for Nanoscale Materials, which is supported by DOE, Office of Science, BES (#DE-AC02-06CH11357).