Self-consistent theory for ferromagnetism induced by photo-excited carriers

The paramagnetic–ferromagnetic phase transition in diluted magnetic semiconductors induced by spin carriers is studied theoretically. A self-consistent formalism to describe the phase transition is developed on the basis of the mean field approximation and the coherent potential approximation. It is predicted that the Curie temperature is maximized at a relatively low concentration of carrier density, and decreases to zero for over-doping.