Soft X-ray spectroscopy of diluted magnetic semiconductor Ga 1−xM xN (M = Cr, Mn)

Abstract

We have performed N 1s–2p soft X-ray emission (SXES) and N 1s absorption (XAS) spectroscopy of recently discovered diluted magnetic semiconductor Ga 1−xM xN (M = Cr, Mn). The SXES spectra of doped GaN shows an additional structure on top of the valence band although the rest of the valence band features do not change compared to non-doped GaN SXES spectrum. The XAS spectra of doped samples also show an additional structure in the band gap of GaN, just below the conduction band minimum. Cr substitution results in larger changes in the unoccupied density of states compared to Mn substitution. These results indicate strong hybridization between N 2p and transition metal 3d electrons in Cr or Mn doped GaN. Comparison of the change in the occupied and unoccupied density of states with band structure calculations for the un-doped and doped compositions indicate that the new states correspond to spin split e g and t 2g states.