  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.
