A view from inside iron-based superconductors

TL;DR

This paper reviews how muon spin spectroscopy reveals microscopic properties of iron-based superconductors, including phase diagram mapping and coexistence of magnetism and superconductivity, under various doping and pressure conditions.

Contribution

It provides a comprehensive overview of muon spin spectroscopy applications in understanding the complex phase behavior of iron-based superconductors.

Findings

Probes entire phase diagram from magnetic to superconducting phases.

Unravels modifications of order parameters with doping and pressure.

Detects nanoscopic coexistence of magnetism and superconductivity.

Abstract

Muon spin spectroscopy is one of the most powerful tools to investigate the microscopic properties of superconductors. In this manuscript, an overview on some of the main achievements obtained by this technique in the iron-based superconductors (IBS) are presented. It is shown how the muons allow to probe the whole phase diagram of IBS, from the magnetic to the superconducting phase, and their sensitivity to unravel the modifications of the magnetic and the superconducting order parameters, as the phase diagram is spanned either by charge doping, by an external pressure or by introducing magnetic and non-magnetic impurities. Moreover, it is highlighted that the muons are unique probes for the study of the nanoscopic coexistence between magnetism and superconductivity taking place at the crossover between the two ground-states.