The relationship between the modern and classical Landaus approach to carrier orbital magnetization is studied theoretically within the envelope function approximation, taking ferromagnetic (Ga,Mn)As as an example. It is shown that while the evaluati
on of hole magnetization within the modern theory does not require information on the band structure in a magnetic field, the number of basis wave functions must be much larger than in the Landau approach to achieve the same quantitative accuracy. A numerically efficient method is proposed, which takes advantages of these two theoretical schemes. The computed magnitude of orbital magnetization is in accord with experimental values obtained by x-ray magnetic circular dichroism in (III,Mn)V compounds. The direct effect of the magnetic field on the hole spectrum is studied too, and employed to interpret a dependence of the Coulomb blockade maxima on the magnetic field in a single electron transistor with a (Ga,Mn)As gate.
Spin splitting of photoelectrons in p-type and electrons in n-type III-V Mn-based diluted magnetic semiconductors is studied theoretically. It is demonstrated that the unusual sign and magnitude of the apparent s-d exchange integral reported for GaAs
:Mn arises from exchange interactions between electrons and holes bound to Mn acceptors. This interaction dominates over the coupling between electrons and Mn spins, so far regarded as the main source of spin-dependent phenomena. A reduced magnitude of the apparent s-d exchange integral found in n-type materials is explained by the presence of repulsive Coulomb potentials at ionized Mn acceptors and a bottleneck effect.
