Pairing susceptibility of iron-based superconductors within a two-layer Hubbard model

By using the determinant quantum Monte Carlo method, we studied the dominant pairing susceptibility of iron-based superconductors within an extended Hubbard model, which describes the underlying electronic structure of both iron pnictides and iron chalcogenides. The extended Hubbard model is constructed by two iron layers, each of which forms two sublattices on a square structure. Although the coupling between the two layers has different effects on the behavior of pairings in iron pnictides and iron chalcogenides, our non-biased numerical simulations reveal that the pairing with Sxy symmetry dominates over the studied parameter for both materials.