Digital magnetic heterostructures (DMHs) are semiconductor structures with magnetic impurities (Mn) restricted to some planar arrangements (monolayers) regularly spaced. In the presence of an external magnetic eld, the sp-d exchange interaction between the localized magnetic moments and the itinerant carriers is responsible for a giant spin splitting, of the order of, or even greater than, the cyclotron separation between Landau levels. Here I calculate the electronic structure of group II-VI

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... gital magnetic quantum wells. I solve the Kohn-Sham equations of the spin-density functional theory within the eective mass approximation. Then I calculate some magneto-optical and transport properties which are experimentally relevant. In particular, I investigate the spin dependent physics of these systems from two dierent points of view. First, I focus on eects of the Mn magnetism on the sp-d exchange spin dependent potential, particularly the eect of antiferromagnetic clustering and the eect of dilution (segregation and interdiusion) of the Mn content prole. By considering these eects I reproduce experimental results for the spin splitting ∆E and spin scattering times τ sf [S. A. Crooker et al., Phys. Rev. Lett. 75, 505 (1995); Phys. Rev. B 61, 1736 (2000)]. In the second part I move on to the physics of spin-polarized two-dimensional electron gases (2DEGs), and show the relevance of the strong dependence of the many-body contributions (exchange and correlation) with the spin polarization. In particular, these eects are relevant for the development of quantum Hall ferromagnetic phases. I calculate magnetotransport in the quantum Hall eect regime for DMHs consisting of ZnSe and CdTe. My results reproduce experimental results [R. Knobel et al., Phys. Rev. B 65, 235327 (2002); J. Jaroszy«ski et al., Phys. Rev. Lett. 89, 266802 (2002)] for the dependence with magnetic eld, temperature, development of anomalous resistivities spikes and hysteretic behaviors in many physical properties. xi