Electronic and Magnetic Properties of 3d Transition-Metal-Doped III-V Magnetic Semiconductor

A systematic study based on an ab initio calculation within a local spin density approximation is applied to material design of GaAs- and GaP-base doped by 3d transition metals. It is found that the ferromagnetic (FM) state is ready to achieve by V-, Cr- and Mn-doped GaP and GaAs. (Ga, Cr)P and (Ga, Cr)As are the most promising candidates for high Curie temperature (above room temperature). In order to increase the Curie temperature, the Mg co-doped method is applied to (Ga, Mn)P and (Ga, Mn)As. By the co-doping, the energy difference between the antiferromagnetic state and the FM state is enlarged, and the partial density of states of 3d-Mn at Fermi energy E_F is increased, which increases the Curie temperature of the diluted magnetic semiconductors. By this co-doping, the anti-bonding state of 3d-Mn is pushed up to a higher region, hence the 3d electrons are more delocalized and itinerated. This makes double exchange dominant, and (Ga, Mn)P and (Ga, Mn)As more stable.