title: Tailoring the spin functionality of a hybrid metal-organic interface by means of alkali-metal doping.
abstract: We employ a recently developed purpose-made technique based on spin-resolved two-photon photoemission spectroscopy to study the influence of alkali-metal doping (Cs and Na) on the spin functionality of the interface between a cobalt thin film and the organic semiconductor copper phthalocyanine. We find two alkali-metal-induced effects. First, alkali-metal atoms act as impurities and increase the spin-flip probability for the electrons crossing the interface (detrimental effect). Second, they allow one to modify the interface energy level alignment and, consequently, to enhance the efficiency of spin injection at an arbitrary energy above the Fermi level of the cobalt (intrinsic effect). We show that the intrinsic effect dominates over the detrimental one, opening the possibility to actively tailor the spin functionality of the considered hybrid metal-organic interface by changing the doping concentration.
authors.affiliation: Department of Physics and Research Center OPTIMAS, University of Kaiserslautern, 67663 Kaiserslautern, Germany. cinchett@rhrk.uni-kl.de
authors.forename: Mirko
authors.initials: M
authors.lastname: Cinchetti
authors.forename: Sabine
authors.initials: S
authors.lastname: Neuschwander
authors.forename: Alexander
authors.initials: A
authors.lastname: Fischer
authors.forename: Andreas
authors.initials: A
authors.lastname: Ruffing
authors.forename: Stefan
authors.initials: S
authors.lastname: Mathias
authors.forename: Jan-Peter
authors.initials: JP
authors.lastname: Wüstenberg
authors.forename: Martin
authors.initials: M
authors.lastname: Aeschlimann