T_c-Enhanced Codoping Method for GaAs-based Dilute Magnetic Semiconductors

摘要

Based on ab initio calculations of Ga_{1-x}Mn_xN_yAs_{1-y} andGa_{1-x}Mn_xC_yAs_{1-y}, we propose a new codoping method to enhance the Curietemperature T_c of diluted magnetic semiconductors. The solubility of Mn can beincreased up to high concentration by the codoping of N or C to reduce thelattice and volume expansion caused by Mn doping. It is found that the impurityband of the majority spin is strongly broadened and pushed up into the higherenergy region due to the strong p-d hybridization caused by the codoping, andthe T_c becomes higher than the room temperature at x>0.06.