Antiferromagnetic order and spin dynamics in iron-based superconductors

TLDR

High‑Tc superconductivity in iron pnictides/chalcogenides emerges when static antiferromagnetic order is suppressed, and neutron scattering is essential for probing the resulting magnetic order and spin dynamics. The review addresses the fundamental question of how magnetism influences superconductivity in iron‑based materials by summarizing neutron‑scattering findings across doping and substitution. Modern neutron time‑of‑flight spectrometers enable full‑zone mapping of spin dynamics in iron‑based superconductors, allowing comparison with cuprate and heavy‑fermion systems and revealing common excitation features linked to superconductivity.

Abstract

High-transition temperature (high-$T_c$) superconductivity in the iron pnictides/chalcogenides emerges from the suppression of the static antiferromagnetic order in their parent compounds, similar to copper oxides superconductors. This raises a fundamental question concerning the role of magnetism in the superconductivity of these materials. Neutron scattering, a powerful probe to study the magnetic order and spin dynamics, plays an essential role in determining the relationship between magnetism and superconductivity in high-$T_c$ superconductors. The rapid development of modern neutron time-of-flight spectrometers allows a direct determination of the spin dynamical properties of iron-based superconductors throughout the entire Brillouin zone. In this review, we present an overview of the neutron scattering results on iron-based superconductors, focusing on the evolution of spin excitation spectra as a function of electron/hole-doping and isoelectronic substitution. We compare spin dynamical properties of iron-based superconductors with those of copper oxide and heavy fermion superconductors, and discuss the common features of spin excitations in these three families of unconventional superconductors and their relationship with superconductivity.