The anisotropy of optical conductivity derived from the energy splitting in iron arsenides

We examine the anisotropy of optical conductivity above the Néel temperature in iron arsenides by mean-field calculation in a five-band Hubbard model. In order to represent the anisotropy, we artificially introduce the energy splitting between d_zx and d_yz. The calculated spectra are not enough to explain the anisotropy observed in experiments. The optical conductivity in the low-energy region is consistent with the observation, while in the high-energy region not. This implies that there should be some other effects to give rise to the anisotropy in the high-energy region.