$Ab$-$initio$ electronic structure, optical and magneto-optical properties of $MnGaAs$ digital ferromagnetic heterostructures

We report on a theoretical study of the electronic, optical and magneto-optical properties of digital ferromagnetic hetero-structures based on $Mn$ $\delta$–doped $GaAs$. We consider different structures corresponding to $Mn$ contents within the range 12-50% and we study how the system changes as a function of the doping concentration. Our first–principles approach includes the spin-orbit interaction in a fully relativistic pseudopotential scheme and the local fields effect in the description of the optical absorption. We show that $Mn$ $\delta$-doped $GaAs$ shares many properties with the uniformly doped $G{a}_{1-x}M{n}_{x}As$ system, i.e. half-metallicity, similar absorption spectra, and moderate Kerr rotation angles in the visible spectral region.