Determining the Short-Range Spin Correlations in Cuprate Chain Materials with Resonant Inelastic X-ray Scattering

TL;DR

This study uses resonant inelastic x-ray scattering to identify high-energy excitations in cuprate chain materials, revealing their temperature-dependent short-range spin correlations with high sensitivity.

Contribution

It demonstrates a novel method to probe short-range spin correlations in cuprates via high-energy excitations at the oxygen K-edge.

Findings

Identification of Zhang-Rice singlet exciton at 3.5 eV

Temperature dependence reveals short-range spin correlations

High sensitivity to spin dynamics at 1 meV scale

Abstract

We report a high-resolution resonant inelastic soft x-ray scattering study of the quantum magnetic spin-chain materials Li2CuO2 and CuGeO3. By tuning the incoming photon energy to the oxygen K-edge, a strong excitation around 3.5 eV energy loss is clearly resolved for both materials. Comparing the experimental data to many-body calculations, we identify this excitation as a Zhang-Rice singlet exciton on neighboring CuO4-plaquettes. We demonstrate that the strong temperature dependence of the inelastic scattering related to this high-energy exciton enables to probe short-range spin correlations on the 1 meV scale with outstanding sensitivity.