title: Dynamic spin filtering at the Co/Alq3 interface mediated by weakly coupled second layer molecules.
abstract: Spin filtering at organic-metal interfaces is often determined by the details of the interaction between the organic molecules and the inorganic magnets used as electrodes. Here we demonstrate a spin-filtering mechanism based on the dynamical spin relaxation of the long-living interface states formed by the magnet and weakly physisorbed molecules. We investigate the case of Alq3 on Co and, by combining two-photon photoemission experiments with electronic structure theory, show that the observed long-time spin-dependent electron dynamics is driven by molecules in the second organic layer. The interface states formed by physisorbed molecules are not spin-split, but acquire a spin-dependent lifetime, that is the result of dynamical spin-relaxation driven by the interaction with the Co substrate. Such spin-filtering mechanism has an important role in the injection of spin-polarized carriers across the interface and their successive hopping diffusion into successive molecular layers of molecular spintronics devices.
authors: School of Physics, AMBER and CRANN Institute, Trinity College, Dublin 2, Ireland.|Nano-Bio Spectroscopy Group and European Theoretical Spectroscopy Facility (ETSF), Universidad del Pais Vasco CFM, CSIC-UPV/EHU-MPC &DIPC, Avenue Tolosa 72, 20018 San Sebastian, Spain.
authors: Andrea
authors: A
authors: Droghetti
authors: Department of Physics and Research Center OPTIMAS, University of Kaiserslautern, Erwin-Schroedinger Strasse 46, 67663 Kaiserslautern, Germany.|Graduate School of Excellence Materials Science in Mainz, Gottlieb-Daimler-Strasse 47, 67663 Kaiserslautern, Germany.
authors: Philip
authors: P
authors: Thielen
authors: School of Physics, AMBER and CRANN Institute, Trinity College, Dublin 2, Ireland.|National Physical Laboratory, Teddington TW11 0LW, UK.
authors: Ivan
authors: I
authors: Rungger
authors: Department of Physics and Research Center OPTIMAS, University of Kaiserslautern, Erwin-Schroedinger Strasse 46, 67663 Kaiserslautern, Germany.
authors: Norman
authors: http://orcid.org/0000-0002-2124-1482
authors: N
authors: Haag
authors: Department of Physics and Research Center OPTIMAS, University of Kaiserslautern, Erwin-Schroedinger Strasse 46, 67663 Kaiserslautern, Germany.
authors: Nicolas
authors: N
authors: Großmann
authors: Department of Physics and Research Center OPTIMAS, University of Kaiserslautern, Erwin-Schroedinger Strasse 46, 67663 Kaiserslautern, Germany.
authors: Johannes
authors: J
authors: Stöckl
authors: Department of Physics and Research Center OPTIMAS, University of Kaiserslautern, Erwin-Schroedinger Strasse 46, 67663 Kaiserslautern, Germany.|Graduate School of Excellence Materials Science in Mainz, Gottlieb-Daimler-Strasse 47, 67663 Kaiserslautern, Germany.
authors: Benjamin
authors: B
authors: Stadtmüller
authors: Department of Physics and Research Center OPTIMAS, University of Kaiserslautern, Erwin-Schroedinger Strasse 46, 67663 Kaiserslautern, Germany.
authors: Martin
authors: M
authors: Aeschlimann
authors: School of Physics, AMBER and CRANN Institute, Trinity College, Dublin 2, Ireland.
authors: Stefano
authors: S
authors: Sanvito
authors: Department of Physics and Research Center OPTIMAS, University of Kaiserslautern, Erwin-Schroedinger Strasse 46, 67663 Kaiserslautern, Germany.
authors: Mirko
authors: M
authors: Cinchetti