A first-principles study of dual acceptors behaviors in Mn δ-doped digital ferromagnetic heterostructures

The effect of the dual acceptors (Mn and Be) on ferromagnetism in δ-doped GaAs/AlAs digital ferromagnetic heterostructures (DFH) has been studied by ab initio calculations. The dependence of the electronic and magnetic properties on both doping acceptor positions in the well and in the barrier are reported in the two-dimensional hole gas system, respectively. Our results also show that the δ-doping Mn layer in the well edge of the DFH is potential for high Curie temperature of a diluted magnetic semiconductor (DMS). The hole distributions and the magnetic moments are analyzed in terms of their orbital projected density of states. The ferromagnetic coupling is attributed to the overlap of the hole gases and the magnetic layer. However, the Be δ-doping layer in AlAs barrier strongly suppresses the ferromagnetic coupling in the DFH, the origin is not from the electrical doping impurities, but rather be the result of some structural modifications due to the presence of the Be.