Spin- and Angle-Resolved Photoemission Study of the Alq3/Co Interface

Abstract

Controlling the interaction between organic semiconductors and ferromagnetic surfaces is one of the key issues for designing metal–organic hybrid interfaces for spintronic applications. The strong chemical interaction across such hybrid interfaces results in the formation of new spin-polarized hybrid interface states which determine all device-relevant properties. Here, we revisit the hybrid interface formed between the prototypical molecule Alq3 and the Co surface using spin- and angle-resolved photoemission. We reveal a significant change of the spectroscopic lineshape of the cobalt 3d bands by the adsorption of Alq3. The hole-like minority and the electron-like majority bands of the bare Co surface are replaced by an energetically very broad band with neglectable band dispersion along the Γ–X direction. Moreover, the magnitude and shape of the spin polarization of the Alq3/Co valence band structure are also significantly modified by the adsorption of Alq3 and become completely independent of the mome...