Bimagnon studies in cuprates with Resonant Inelastic X-ray Scattering at the O K edge. II - The doping effect in La2-xSrxCuO4

TL;DR

This study uses Resonant Inelastic X-ray Scattering at the O K edge to investigate how doping affects magnetic excitations, specifically bimagnons, in La2-xSrxCuO4, revealing persistent spin excitations across doping levels.

Contribution

It provides new insights into doping-dependent magnetic excitations in cuprates using RIXS at the O K edge, focusing on the mid-infrared region and bimagnon continuum.

Findings

Presence of damped bimagnons across doping levels

Higher even order spin excitations with constant spectral weight

Doping does not significantly diminish magnetic excitations

Abstract

We present RIXS data at O K edge from La2-xSrxCuO4 vs. doping between x=0.10 and x=0.22 with attention to the magnetic excitations in the Mid-Infrared region. The sampling done by RIXS is the same as in the undoped cuprates provided the excitation is at the first pre-peak induced by doping. Note that this excitation energy is about 1.5 eV lower than that needed to see bimagnons in the parent compound. This approach allows the study of the upper region of the bimagnon continuum around 450 meV within about one third of the Brilluoin Zone around \Gamma. The results show the presence of damped bimagnons and of higher even order spin excitations with almost constant spectral weight at all the dopings explored here. The implications on high Tc studies are briefly addressed.