| 报告题目 | Spinterfaces as Microscopic Spin Traps |
| 报告人 | Prof. Martin Aeschlimann |
| 报告人单位 | University of Kaiserslautern, GERMANY |
| 报告时间 | 2013-07-17 |
| 报告地点 | 合肥微尺度物质科学国家实验室九楼会议室 |
| 主办单位 | 合肥微尺度物质科学国家实验室 |
| 报告介绍 | Abstract:
Interfaces between ferromagnetic materials and organic semiconductors ? also known as spinterfaces - constitute an incredibly rich playground in the field of spintronics. For example, spinterfaces have the potential to be implemented as tunable spin filters [1,2], which will pave the way to a whole new class of advanced, i.e., actively controlled spintronics devices. The progress in the field of spinterface science depends thus critically on elucidating the still unexplored spin-dependent carrier dynamics at such hybrid interfaces. Spin- and time-resolved two-photon photoemission (2PPE) allows to study the dynamics of the relevant hybrid electronic interface structure that determines the spin-filtering efficiency. In a real-time pump-probe experiment, we follow the spin-dependent trapping of excited electrons at the prototypical interface between the ferromagnet cobalt and the metalorganic complex tris-(8-hydroxyquinolinato) aluminium (Co-Alq3 interface). The pump photon is used to populate an unoccupied hybrid state at the Co-Alq3 interface with a transient spin-polarization. The transiently populated hybrid state is probed by analyzing the photoemitted electrons with respect to their kinetic energy, spin and momentum. This gives access to the relevant transient femtosecond-to-picosecond electron dynamics in the hybrid interface state that eventually determine the spin filtering efficiency of the spinterface. We observe a substantial spin-dependent confinement of electrons at the interface [3]. Such spin-dependent trapping behavior elucidates the fundamental microscopic origin of the spin-filtering properties at spinterfaces, which is important for the design of next-generation spintronics devices based on tunable organic spin filters. [1]M. Cinchetti, K. Heimer, J.-P. Wuestenberg, O. Andreyev, M. Bauer, S. Lach, C. Ziegler, Y. Gao, and M. Aeschlimann, Nature Materials 8, 115 (2008). [2]M. Cinchetti, S. Neuschwander, A. Fischer, A. Ruffing, S. Mathias, J.-P. Wuestenberg, and M. Aeschlimann, Phys. Rev. Lett. 104, 1 (2010). [3]S. Steil, N. Grossmann, M. Laux, A. Ruffing, D. Steil, M. Wiesenmayer, S. Mathias, O. L. A. Monti, M. Cinchetti, and M. Aeschlimann, Nature Physics 9, 242 (2013). |
