The Nature of the magnetism-promoting hole state in the prototype   magnetic semiconductor GaAs: Mn
  Recent experiments [1] suggest that the ferromagnetism (FM) in GaAs: Mn is determined by the impurity band rather than holes in the valence band. We discuss here the physical mechanism of FM mediated by the carriers in impurity band, where the Mn d-level play a crucial role. The theory is based on the first principle approach. 
V. Fleurov, K. Kikoin, and A. Zunger
cond-mat.mes-hall cond-mat.mtrl-sci cond-mat.str-el