Abstract
<jats:p>The effect of spin-orbit coupling on the band structure and Fermi surface in a ten-orbital model of iron pnictides is studied. Since there are two iron ions in the unit cell, which are connected through arsenic orbitals, constants responsible for the spin-orbit coupling between and within the ions are introduced in the effective model in order to study how these contributions affect the band structure. We show that the intra- and inter-ion parts of the spin-orbit coupling affect the topology of the Fermi surface by splitting four Fermi contours around the point M = (π, π). At the same time, such a change appears even if there is only an intra-ion spin-orbit coupling; the finite inter-ionic spin-orbit coupling is not required for that.</jats:p>