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 x and hole n densities, and the impurity-hole exchange J in units of the hop-ping t. Optimal values are found in the subtle intermediate regime between itinerant and localized carriers. At intermediate and large J/t, a "clustered" state is observed above the Curie temperature and ferromagnetism is suppressed. Formal analogies between DMS and manganites are discussed.
Alvarez
Gonzalo
G
National High Magnetic Field Lab and Department of Physics, Florida State University, Tallahassee, FL 32310, USA.
Mayr
Matthias
M
Dagotto
Elbio
E