Initial stages of Mn adsorption on Ge(111)

The initial stages of growth of Mn on Ge(111) were studied with scanning tunneling microscopy, x-ray photoelectron spectroscopy, and first-principles density functional theory calculations. Mn atoms adsorb on the H₃ sites of the Ge(111)-c(2×8) reconstruction, a process that is usually accompanied by a registry shift (along the [11̅ 0] direction) of an adjacent Ge adatom row. Deposition of approximately one monolayer of Mn and subsequent annealing results in the formation of Mn₅Ge₃ islands. Epitaxial Mn₅Ge₃ films can be grown from a solid-state reaction between the Mn deposit and Ge substrate. The Mn₅Ge₃ films are ferromagnetic metals with a magnetic moment of 2.6 μ_B per Mn, as determined from the Mn 3s exchange splitting in XPS. Theoretical calculations of the adsorption sites, surface structures, and electronic structure all agree exceedingly well with the experimental observations.