Nematic orders in iron-based superconductors

In the newly discovered iron-based superconductor, many experiments have demonstrated the existence of the rotational symmetry breaking nematic order, which has been a prevailing phenomena in many correlated electronic systems. In this paper, we review nematic behaviors in iron-pnictides and the mechanism behind the development of the nematic order. We discuss evidence that supports spin-driven nematicity, and review theories, results and predictions derived from magnetic models.

► This article reviews the studies on magnetism and nematic order in iron-based superconductors.
► Ginzburg–Landau theory, spin-wave expansion, 1/N expansion will be used in this paper.
► Phase diagram including the nature of phase transitions are analyzed.
► Theoretical results are compared with the experimental facts on iron-pnictides materials.