Study of magnetic, nematic and superconducting properties of iron-based high-temperature superconductors: Variational cluster approximation

Two-orbital model describing iron-based high-temperature superconductors is studied within the limits of variational cluster approximation. It is found that in the undoped regime the stripe antiferromagnetic ordering is realized, while in doped regime antiferromagnetism and superconductivity coexist. In the superconducting state, two types of symmetry are found: extended inter-orbit s-wave and intra-orbit d-wave, in agreement with known experimental results.