Electronic properties of the ordered metallic Mn:Ge(111) interface

The electronic and structural properties of an Mn:Ge(111) ordered interface produced by annealing Mn multilayers evaporated on a Ge(111) single crystal have been investigated. After annealing above 300 K, the surface always showed a (root 3 x root 3)R30 degrees reconstruction. The interface obtained after the evaporation of 4 ML has been selected for electronic spectroscopy studies, while thicker layers have been prepared for magnetization measurements. A ferromagnetic ordering with a T-c of about 260 K was detected. The Mn 2p XAS and XPS spectra indicate that the Mn:Ge(111) interface is metallic, and resonant photoemission spectra collected across the Mn 2p -> 3d absorption edge display characteristic many-electron effects for the Mn spectral weight in the valence band, with a significant contribution of Mn-derived states at the Fermi edge.