Magnetism and electronic properties of Mn:Ge(111) interfaces probed by core level photoemission spectroscopy

The electronic and magnetic properties of Mn:Ge(111) interfaces have been investigated by photoelectron spectroscopy and SQUID magnetometry. An ordered, metallic and ferromagnetic, Mn:Ge(111) interface and a disordered, semiconducting and paramagnetic, Mn_xGe_1-x surface alloy have been considered. An analysis of the Mn 2p X-ray photoemission core line shows that the former interface can be described by a single-configuration Mn 3d⁶ initial state, while the latter presents satellite features typical of Mn-based diluted magnetic semiconductors, characterized by relevant ligand-to-metal charge transfer effects.