Critical scattering in the vicinity of the metal-insulator transition in Mn-doped GaAs

We have developed an improved model for describing the electrical transport properties of diluted ferromagnetic semiconductors such as Mn-doped GaAs. The model takes into account transport mechanisms in disordered semiconductors in the vicinity of the metal-insulator transition and the critical scattering due to the exchange interaction between the charge carrier spins and the localized magnetic moments. The model is based on Kubo-Greenwood formalism and the scaling theory of localization. The contribution from the critical scattering is calculated using the Green's function technique and the self-consistent Born approximation. The model explains well the measured resistivity in Mn-doped GaAs as a function of temperature, doping concentration, and magnetic field.