First-principles study of strain effects on Mn in Si

The effects of strain on Mn impurities in Si were investigated by using first-principles calculations. It is shown that substitutional Mn is stabilized and that the magnetic moment is maintained when a tensile strain is given. This suggests that the tensile strain is effective for improving the crystallinity of epitaxial films. Under high Mn concentration conditions, the substitutional Mn complex can cause a structural change and decrease the lattice constant of the crystal. Thus, the formation of shrinked epitaxial films can cause a structural change related to the substitutional Mn complexes, which might make it impossible to obtain the ferromagnetic property