The influence of external strain on the diffusion barriers of interstitial Mn in GaAs was studied using first-principles calculations within the density functional theory. The diffusion barrier changed with strain in different manners: linear on the tensile strain and nonlinear on compressive strain, in contrast to the linear behaviour of the continuum elastic model. The discrepancy between the continuum elastic model and the results of the first-principles method was attributed to the energy-level crossing caused by strain. Moreover, it was found that the external strain could not only effectively change the diffusion barrier (even to zero, at certain strain), but also the position of saddle points along the migration path. These findings provided an alternative way to reduce the population of interstitial Mn in GaAs, thus correspondingly to increase the Curie temperature of this system.

Strain Effect on the Diffusion of Interstitial Mn in GaAs. Z.T.Wang, S.Chen, X.M.Duan, S.H.Wei, D.Y.Sun, X.G.Gong: Journal of Physics - Condensed Matter, 2012, 24[21], 215801