Mn Solid Solutions in Self-Assembled Ge/Si (001) Quantum Dot   Heterostructures
  Heteroepitaxial Ge0.98Mn0.02 quantum dots on Si (001) were grown by molecular beam epitaxy. The standard Ge wetting layer-hut-dome-superdome sequence was observed, with no indicators of second phase formation in the surface morphology. We show that Mn forms a dilute solid solution in the Ge quantum dot layer, and a significant fraction of the Mn partitions into a sparse array of buried, Mn-enriched silicide precipitates directly underneath a fraction of the Ge superdomes. The magnetic response from the ultra-thin film indicates the absence of robust room temperature ferromagnetism, perhaps due to anomalous intermixing of Si into the Ge quantum dots. 
Joseph Kassim, Christopher Nolph, Matthieu Jamet, Petra Reinke and   Jerrold Floro
cond-mat.mtrl-sci