Convergence study of the ab-initio calculated quadratic magneto-optical spectra in bcc Fe

Using the WIEN2k code, we perform ab-initio calculations of the electronic structure and the permittivity tensor of bcc Fe with magnetization along the [001] and [011] directions. The electronic structure is calculated with various numbers of k-points in the full Brillouin zone and the convergence of the calculated data is being studied. Two exchange-correlation potentials are employed, namely LDA and GGA, and their effect on the outcoming spectra is shown. The permittivity tensor is obtained from the electronic structure by the Kubo formula. From the permittivity tensor the complex spectra of linear (K) and quadratic (Gs, 2G44) magneto-optical parameters are extracted. The spectra are compared to the literature.