Tc-enhanced codoping method for GaAs-based dilute magnetic semiconductors

Based on ab initio calculations of Ga1-xMnxNyAs1-y and Ga1-xMnxCyAs1-y, we propose a new codoping method to enhance the Curie temperature T-c of diluted magnetic semiconductors. The solubility of Mn can be increased up to high concentration by the codoping of N or C to reduce the lattice and volume expansion caused by Mn doping. It is found that the impurity band of the majority spin is strongly broadened and pushed up into the higher energy region due to the strong p-d hybridization caused by the codoping, and the T-c becomes higher than the room temperature at x > 6%.