Doping Dependent Changes in Nitrogen 2$p$ States in the Diluted Magnetic   Semiconductor Ga$_{1-x}$Cr$_{x}$N
  We study the electronic structure of the recently discovered diluted magnetic semiconductor Ga$_{1-x}$Cr$_{x}$N ($x$ = 0.01-0.10). A systematic study of the changes in the $occupied$ and $unoccupied$ ligand (N) partial density of states (DOS) of the host lattice is carried out using N 1$s$ soft x-ray emission and absorption spectroscopy, respectively. X-ray absorption measurements confirm the wurtzite N 2$p$ DOS and substitutional doping of Cr into Ga-sites. Coupled changes in the $occupied$ and $unoccupied$ N 2$p$ character DOS of Ga$_{1-x}$Cr$_{x}$N identify states responsible for ferromagnetism consistent with band structure calculations. 
T. Takeuchi, Y. Harada, T. Tokushima, M. Taguchi, Y. Takata, A.   Chainani, J. J. Kim, H. Makino, T. Yao, T. Yamamoto, T. Ts...