Calculated x-ray linear dichroism spectra for Gd-doped GaN

Calculations of the x-ray linear dichroism (XLD) spectra of the Ga K edge in GaN and the Gd L₃ edge in Gd doped GaN are presented. We show that these spectra can be modeled using partial densities of states standardly available in density functional band structure programs. We find good agreement with recent experiments for Gd on Ga site, showing that there is no need to invoke Gd on N or other sites to explain the spectra as previously claimed in the literature based on multiple scattering simulations.