A Short Review of the $S_4$ Symmetric Microscopic Model for Iron-Based High Temperature Superconductors

TL;DR

This paper reviews an $S_4$ symmetric two-orbital microscopic model for iron-based high-temperature superconductors, explaining pairing mechanisms, unifying different families, and aligning with experimental observations through numerical simulations.

Contribution

It introduces a faithful $S_4$ symmetric model that captures the low-energy physics and explains superconductivity and band reconstruction in iron-based superconductors.

Findings

Provides a physical picture for pairing symmetry.

Unifies different iron-based superconductor families.

Supports the $S_4$ model with quantum Monte Carlo results.

Abstract

We briefly review the recently constructed two orbital microscopic model for iron-based superconductors based on $S_4$ symmetry (PRX 2 021009(2012)). With this faithful representation of the kinematics of the tri-layer FeAs or FeSe structure, the model provides answers and physical pictures to fundamental questions related to the robustness of superconductivity and pairing symmetry, unifies different families of iron-based superconductors, casts new insight into the connections to the other high $T_c$ superconductors, cuprates, and reveals why an s-wave pairing can be stabilized by repulsive interactions. Further progresses include that the model provides a clean understanding of band reconstruction observed in magnetically ordered states, which is a strong support to the kinematics of the $S_4$ model, and captures the essential low energy physics of iron-based superconductors based on numerical results from unbiased quantum Monte Carlo simulation.