The minimum model for the iron-based superconductors

Jian Li; Yupeng Wang

paper

The minimum model for the iron-based superconductors

arXiv:0805.0644

Abstract

A single band $t$ - $U$ - $J_{1}$ - $J_{2}$ model is proposed as the minimum model to describe the superconductivity of the newly discovered iron-based superconductors $R (O_{1 - x} F_{x}) F e A s$ and $R O_{1 - x} F e A s$ ( $R = L a, C e, S m, P r, N d, G d$ ). With the mean-field approach, it is found that the pairing occurs in the d-wave channel. In the likely parameter region of the real materials, by lowering temperature, the system enters firstly the $d_{x y}$ superconducting phase with $D_{4 h}$ -symmetry and then enters the time-reversal-symmetry-broken $d_{x y} + i d_{x^{2} - y^{2}}$ superconducting phase with $C_{4 h}$ -symmetry.

3 pages, 3 figures