# Unified phase diagram for iron-based superconductors

## TL;DR

This paper proposes a unified phase diagram for iron-based superconductors by linking magnetic order and nematic fluctuations, suggesting they are strongly correlated systems with a common underlying mechanism.

## Contribution

It introduces a novel scaling relation between ordered moments and nematic susceptibility, enabling a unified understanding of diverse iron pnictides.

## Key findings

- Ordered moments inversely proportional to nematic susceptibility
- Magnetic ground states tuned by nematic fluctuations
- Unified phase diagram for iron-based superconductors

## Abstract

High-temperature superconductivity is closely adjacent to a long-range antiferromagnet, which is called a parent compound. In cuprates, all parent compounds are alike and carrier doping leads to superconductivity, so a unified phase diagram can be drawn. However, the properties of parent compounds for iron-based superconductors show significant diversity and both carrier and isovalent dopings can cause superconductivity, which casts doubt on the idea that there exists a unified phase diagram for them. Here we show that the ordered moments in a variety of iron pnictides are inversely proportional to the effective Curie constants of their nematic susceptibility. This unexpected scaling behavior suggests that the magnetic ground states of iron pnictides can be achieved by tuning the strength of nematic fluctuations. Therefore, a unified phase diagram can be established where superconductivity emerges from a hypothetical parent compound with a large ordered moment but weak nematic fluctuations, which suggests that iron-based superconductors are strongly correlated electron systems.