Phase Diagram of a Model for Diluted Magnetic Semiconductors Beyond Mean-Field Approximations

A lattice spin-fermion model for diluted magnetic semiconductors (DMS) is investigated numerically, improving on previously used mean-field approximations. Curie temperatures are obtained varying the Mn spin [Formula presented] and hole [Formula presented] densities, and the impurity-hole exchange [Formula presented] in units of the hopping [Formula presented]. Optimal values are found in the subtle intermediate regime between itinerant and localized carriers. At intermediate and large [Formula presented], a “clustered” state is observed above the Curie temperature and ferromagnetism is suppressed. Formal analogies between DMS and manganites are discussed.