Two characteristic energies in the low-energy antiferromagnetic response of the electron-doped high-temperature superconductor Nd$_{2-x}$Ce$_x$CuO$_{4+\delta}$

TL;DR

This study uses inelastic neutron scattering to identify two characteristic magnetic energies in the superconducting state of electron-doped Nd$_{2-x}$Ce$_x$CuO$_{4+ abla}$, linking them to electronic Raman features and challenging previous resonance mode claims.

Contribution

It reveals two characteristic energies in the magnetic response of Nd$_{2-x}$Ce$_x$CuO$_{4+ abla}$ and connects them to electronic Raman scattering features, providing new insights into the magnetic excitations in electron-doped cuprates.

Findings

Identified two magnetic energies at 6.4 meV and 4.5 meV in the superconducting state.

Linked these energies to electronic Raman scattering features.

Challenged previous claims of a magnetic resonance mode near 10 meV.

Abstract

Inelastic neutron scattering for Nd$_{2-x}$Ce$_x$CuO$_{4+\delta}$ near optimal doping ($x \approx 0.155$, $T_{c} = 25 \mathrm{K}$) reveals that the dynamic magnetic susceptibility at the antiferromagnetic zone center exhibits two characteristic energies in the superconducting state: $\omega_1 \approx 6.4 \mathrm{meV}$ and $\omega_2 \approx 4.5 \mathrm{meV}$. These two magnetic energies agree $quantitatively$ with the $B_{1g}$ / $B_{2g}$ and $A_{1g}$ features previously observed in electronic Raman scattering, where the former is believed to indicate the maximum electronic gap and the origin of the smaller $A_{1g}$ feature has remained unexplained. The susceptibility change upon cooling into the superconducting state is inconsistent with previous claims of the existence of a magnetic resonance mode near 10 meV, but consistent with a resonance at $\omega_2$.