Ferromagnetism and transport in diluted magnetic semiconductors
This dissertation focuses on the study of ferromagnetism in Dilute Magnetic Semiconductors. To study these strongly correlated electronic systems, two non- perturbative techniques are used: the Dynamical Mean Field Approximation (DMFA) and the Dynamical Cluster Approximation (DCA). The model used for Dilute Magnetic Semiconductors (DMS) incorporates the strong spin-orbit couplings of the carrier holes as found in most III-V semiconductors doped with manganese such as Ga1-xMnxAs. Calculated within the DMFA, the spin-orbit coupling effects give rise to various interesting physics, primarily the anisotropic behavior of the impurity band that affect the charge transport properties in the ferromagnetic phase. We show that non-local correlations, within the DCA, are responsible for magnetic frustration and magnetic reorientation of the DMS. The DMFA is employed to study ferromagnetism and transport in Ga1-xMnxAs, using the sp3 tight-binding Hamiltonian. Finally, employing the sp3 tight-binding Hamiltonian and the DMFA, ferromagnetism in a wide band gap Ga1-xMnxN is studied.
Magnetic Semiconductors, Dynamical Mean Field Approximation, Dynamical Cluster Approximation
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