Solid phase epitaxy of ferromagnetic MnAs dots on GaMnAs layers
  Formation of MnAs quantum dots in a regular ring-like distribution has been found on MBE-grown (GaMn)As surfaces after low-temperature annealing under As capping. The Mn was supplied by out-diffusing Mn interstitials from (GaMn)As. With 5 at% substitutional Mn the quantum dots appeared for (GaMn)As layers thicker than 500 A. For thinner layers the Mn-rich surfaces, presumably monolayer thick MnAs, are smooth and well-ordered (1x2), and are well suited for continued epitaxial growth. 
J. Sadowski, M. Adell, J. Kanski, L. Ilver, E. Janik, E. Lusakowska,   J. Z. Domagala, R. Brucas, M. Hanson