Electrons in organic semiconductors (OSC) possess remarkably long spin relaxation times. Hybrid spintronic devices that combine OSC with ferromagnetic (FM) substrates are therefore expected to provide a route to devices with improved and new functionalities. A crucial role is played by the FM‐OSC interface which governs the spin injection into the OSC. Using spin‐resolved photoelectron spectroscopy and ab initio calculations we study here such possible injection channels in metal phthalocyanines (MPc). We report the first direct observation of the successful engineering of different spin‐selective hybrid interface states at the Fermi level of a FM‐OSC hybrid junction only by changing the central metal atom of a MPc. Our results demonstrate that tailoring the chemical interaction at the FM‐OSC interface is a promising way to modify the spin injection channels and thus the spin injection capability.

The valence band structure of different metal-phthalocyanines was investigated by comparing ultraviolet photoelectron spectra at different excitation energies with simulated spectra that take the different photoionization cross-sections at these energies into account. The Kohn-Sham eigenvalue spectra, derived from density functional theory calculations, using hybrid exchange-correlation functionals, were weighted with the photoionization coefficients in accordance with the used excitation energy. By applying these techniques, the differences in the photoelectron spectra using He I and He II radiation can be reproduced and investigated. It will be shown that the 3d-orbitals of the used metal central atom of these molecules have a major influence. The changes at different excitation energies were studied for Fe, Co, and Cu central atoms to describe the chemical tailoring effects.

Understanding the very promising, highly spin polarized, foundation system TCNE/Co(100) for future spintronic architecture, using an advanced multi method approach.