Roles of Hund's coupling in the spin-wave excitations of SDW state in iron pnictides

Abstract

We investigate the role of Hund's coupling in the spin-wave excitations of the (\(\pi, 0\)) ordered magnetic state within a five-orbital tight-binding model for iron pnictides. To differentiate between the roles of intraorbital Coulomb interaction and Hund's coupling, we focus on the self-consistently obtained mean-field SDW state with a fixed magnetic moment obtained by using different sets of interaction parameters. We find that the Hund's coupling is crucial for the description of various experimentally observed characteristics of the spin-wave excitations including the anisotropy, energy-dependent behavior, and spin-wave spectral weight distribution.