The lattice location of Mn in heavily p-type doped GaAs by means of β− emission channelling from the decay of 56Mn was studied. The majority of the Mn atoms substituted for Ga and up to 31% occupy the tetrahedral interstitial site with As nearest neighbours. Contrary to the general belief, it was found that interstitial Mn was immobile up to 400C, with an activation energy for diffusion of 1.7 to 2.3eV. Such high thermal stability of interstitial Mn had significant implications for the strategies and prospects for achieving room temperature ferromagnetism in Ga1−xMnxAs.

Direct Identification of Interstitial Mn in Heavily p-Type Doped GaAs and Evidence of its High Thermal Stability. L.M.C.Pereira, U.Wahl, S.Decoster, J.G.Correia, M.R.da Silva, A.Vantomme, J.P.Araújo: Applied Physics Letters, 2011, 98[20], 201905