Theory of carrier mediated ferromagnetism in dilute magnetic oxides

Theory of Ferromagnetism in Diluted Magnetic Semiconductors

Carrier-induced ferromagnetism has been observed in several (III,Mn)V semiconductors. We review the theoretical picture of these ferromagnetic semiconductors that emerges from a model with kinetic-exchange coupling between localized Mn spins and valence-band carriers. We discuss the applicability of this model, the validity of a mean-field approximation for its interaction term widely used in t...

Mechanism of carrier-induced ferromagnetism in magnetic semiconductors

Taking into account both random impurity distribution and thermal fluctuations of localized spins, we have performed a model calculation for the carrier (hole) state in Ga1−xMnxAs by using the coherent potential approximation (CPA). The result reveals that a p-hole in the band tail of Ga1−xMnxAs is not like a free carrier but is rather virtually bounded to impurity sites. The carrier spin stron...

Temperature-dependent orbital-moment anisotropy in dilute magnetic oxides

Carrier-mediated ferromagnetism in the magnetic topological insulator Cr-doped (Sb,Bi)2Te3.

Magnetically doped topological insulators, possessing an energy gap created at the Dirac point through time-reversal-symmetry breaking, are predicted to exhibit exotic phenomena including the quantized anomalous Hall effect and a dissipationless transport, which facilitate the development of low-power-consumption devices using electron spins. Although several candidates of magnetically doped to...

Theory of diluted magnetic semiconductor ferromagnetism

We present a theory of carrier-induced ferromagnetism in diluted magnetic semiconductors ( III1-xMnxV) which allows for arbitrary itinerant-carrier spin polarization and dynamic correlations. Both ingredients are essential in identifying the system's elementary excitations and describing their properties. We find a branch of collective modes, in addition to the spin waves and Stoner continuum w...