  The relationship between the modern and classical Landau's 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 evaluation 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.

Materials Science