Coexistence of Jahn-Teller effect and AFM in two-orbital model for s[formula omitted]-wave iron based superconductors

Abstract

The origin of pairing mechanism and the coexisting order parameters in Fe-based superconductors have been attracting increasing attention. The tetragonal to orthorhombic phase transition which leads the antiferromagnetic phase transition in many Fe-based superconductors is one of the current heat discussions of electronic order. The distortion and antiferromagnetism coexist in the phase diagrams of such superconductors. A tight-binding two band model with the coexistence of Jahn-Teller distortion and antiferromagnetism is being proposed here for s±-wave pairing symmetry of the form coskx×cosky in the mean field approximation. The model is solved by Zubarev’s double-time Green’s function technique to find their self-consistent gap equations. Then these gap equations are solved self-consistently numerically and the specific heat, density of states and band energies are studied for the system.