Superconductivity and Jahn-Teller Distortion in s±-Wave Iron-Based Superconductors

We discuss here a few possibilities of gap structure and pairing mechanism for iron-based superconductors with more than one orbital symmetry contributing to the pairing. We have proposed a two-orbital tight-binding model for the coexistence of superconductivity and Jahn-Teller distortion in s(+/-)-wave pairing symmetry of the form cosk(x) x cosk(y) in the mean-field approximation. The self-consistent gap equations are calculated by Zubarev's double-time Green's function technique which are solved numerically and self-consistently. The specific heat, density of states and band energies are also studied for the proposed model.