arXiv:1211.1925 · Physical Review Letters
Determining the Short-Range Spin Correlations in the Spin-Chain Li2CuO2 and CuGeO3 Compounds Using Resonant Inelastic X-Ray Scattering
Claude Monney, Valentina Bisogni, Ke‐Jin Zhou, R. Kraus, Vladimir N. Strocov, G. Behr, Jiřı́ Málek, Roman O. Kuzian, Stefan‐Ludwig Drechsler, Steven Johnston, A. Revcolevschi, Bernd Büchner, Henrik Moodysson Rønnow, Jeroen van den Brink, J. Geck, Thorsten Schmitt
Abstract
We report a high-resolution resonant inelastic soft x-ray scattering study of the quantum magnetic spin-chain materials Li(2)CuO(2) and CuGeO(3). 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 CuO(4) plaquettes. We demonstrate that the strong temperature dependence of the inelastic scattering related to this high-energy exciton enables us to probe short-range spin correlations on the 1 meV scale with outstanding sensitivity.