Based upon first-principles calculations, a solubility control method for magnetic impurities in dilute magnetic semiconductors was proposed. The low solubility of Mn in (Ga,Mn)As was experimentally and theoretically known. It was shown that donor atoms, such as Li, introduced at the interstitial sites in GaAs enhanced the solubility of Mn. As a result, Mn could be doped to more than 20% in GaAs in the thermal equilibrium condition. The same effect could be seen when Mn in GaAs was doped with other interstitial donors, such as H, Na, K, Be, Mg, Ca, Cu, and Ag.

Interstitial Donor Codoping Method in (Ga,Mn)As to Increase Solubility of Mn and Curie Temperature. H.Fujii, K.Sato, L.Bergqvist, P.H.Dederichs, H.Katayama-Yoshida: Applied Physics Express, 2011, 4[4], 043003