High Energy Spin Excitations in Electron-Doped Superconducting Pr$_{0.88}$LaCe$_{0.12}$CuO$_{4-\delta}$ with $T_c=21$ K

TL;DR

This study uses neutron scattering to explore how electron doping affects magnetic excitations in a superconductor, revealing broadening of low-energy spin fluctuations and suppression of high-energy excitations, indicating a new energy scale similar to lightly hole-doped cuprates.

Contribution

It provides detailed insights into the magnetic excitation spectrum of electron-doped Pr$_{0.88}$LaCe$_{0.12}$CuO$_{4-eta}$, highlighting doping-induced spectral redistribution and a new energy scale.

Findings

Wave vector broadening in low-energy spin fluctuations

Suppression of high-energy spin-wave excitations

Identification of a new energy scale in the spin susceptibility

Abstract

We use high-resolution inelastic neutron scattering to study the low-temperature magnetic excitations of electron-doped superconducting Pr$_{0.88}$LaCe$_{0.12}$CuO$_{4-\delta}$ ($T_c=21\pm 1$ K) over a wide energy range (4 meV$\le\hbar\omega\le 330$ meV). The effect of electron-doping is to cause a wave vector ($Q$) broadening in the low-energy ($\hbar\omega\le 80$ meV) commensurate spin fluctuations at ($\pi$,$\pi$) and to suppress the intensity of spin-wave-like excitations at high energies ($\hbar\omega\ge 100$ meV). This leads to a substantial redistribution in the spectrum of the local dynamical spin susceptibility $\chi^{\prime\prime}(\omega)$, and reveals a new energy scale similar to that of the lightly hole-doped YB$_2$Cu$_3$O$_{6.353}$ ($T_c=18$ K).