Theory for the bound magnetic polaron in diluted magnetic semiconductors by a modified molecular-field approximation

A theory for the bound magnetic polaron (BMP) in diluted magnetic semiconductors is presented. The fluctuations of magnetization are taken into account by a modified molecular-field approximation with a variation method for magnetization. The spin-splitting and the spectrum for spin-flip Raman scattering calculated for the electron-type bound magnetic polaron are compared to the experimental results with a good agreement. The present method describes well the energetics of BMP from low temperatures to high temperatures. The method is also applicable to the hole-type bound magnetic polaron where the saturation effect of the magnetization becomes important.