Single-band model for diluted magnetic semiconductors: Dynamical and transport properties and relevance of clustered states

Dynamical and transport properties of a simple single-band spin-fermion lattice model for (III,Mn)V diluted magnetic semiconductors (DMS’s) is here discussed using Monte Carlo simulations. This effort is a continuation of previous work [G. Alvarez et al., Phys. Rev. Lett. 89, 277202 (2002)] where the static properties of the model were studied. The present results support the view that the relevant regime of J/t (standard notation) is that of intermediate coupling, where carriers are only partially trapped near Mn spins, and locally ordered regions (clusters) are present above the Curie temperature T_C. This conclusion is based on the calculation of the resistivity vs temperature, that shows a soft metal-to-insulator transition near T_C, as well on the analysis of the density-of-states and optical conductivity. In addition, in the clustered regime a large magnetoresistance is observed in simulations. Formal analogies between DMS’s and manganites are also discussed.