Ab initiocalculation of electronic properties of periodically Si-δ-doped GaAs

We report an ab initio calculation of periodically Si-\ensuremath{\delta}-doped GaAs, solving the Schr\"odinger equation in a three-dimensional (3D) system. We show, in the regime of high donor concentration, that the subband \ensuremath{\delta}, even for small period (p=45 \AA{}), exhibits small dispersion as does a 2D system. Also, we discuss the stability of the Si sheet in the bulk, and the electronic properties of the clustering ${\mathrm{Si}}_{\mathrm{Ga}\mathrm{\ensuremath{-}}}$${\mathrm{Si}}_{\mathrm{As}}$.