Progress in Neutron Scattering Studies of Spin Excitations in High-Tc Cuprates

TL;DR

This paper reviews recent neutron scattering research on spin excitations in high-Tc cuprates, highlighting experimental advances, variations with doping, and connections to charge/spin order, to better understand high-temperature superconductivity.

Contribution

It provides a comprehensive overview of experimental progress and insights into magnetic spectra and their relation to electronic correlations in cuprates.

Findings

Magnetic spectral weight varies with doping levels.

Connections between spin excitations and stripe order are discussed.

Differences between hole-doped and electron-doped cuprates are analyzed.

Abstract

Neutron scattering experiments continue to improve our knowledge of spin fluctuations in layered cuprates, excitations that are symptomatic of the electronic correlations underlying high-temperature superconductivity. Time-of-flight spectrometers, together with new and varied single crystal samples, have provided a more complete characterization of the magnetic energy spectrum and its variation with carrier concentration. While the spin excitations appear anomalous in comparison with simple model systems, there is clear consistency among a variety of cuprate families. Focusing initially on hole-doped systems, we review the nature of the magnetic spectrum, and variations in magnetic spectral weight with doping. We consider connections with the phenomena of charge and spin stripe order, and the potential generality of such correlations as suggested by studies of magnetic-field and impurity induced order. We contrast the behavior of the hole-doped systems with the trends found in the electron-doped superconductors. Returning to hole-doped cuprates, studies of translation-symmetry-preserving magnetic order are discussed, along with efforts to explore new systems. We conclude with a discussion of future challenges.