SFB Colloquium

Resonant inelastic x-ray scattering (RIXS) is a powerful x-ray spectroscopy that is sensitive to many degrees of freedom of condensed matter. In the last 10 years, the development of the RIXS technique and its application to correlated materials followed a steady and impressive progress. With the advance of x-ray free electron lasers (XFEL), it becomes now possible to perform time-resolved RIXS to access their time-domain dynamics.

Here I will first present static RIXS data obtained at O K-edge on the quasi-one-dimensional spin-chains CuGeO₃ at Swiss Light Source (Paul Scherrer Insitute). In this edge-sharing chain cuprate having a standard Cu d⁹ electronic configuration, RIXS can create a particular excitation called a Zhang-Rice singlet (ZRS) in its final state. I will show how the intensity of this ZRS excitation depends on the ground state spin configuration and is a measure of the nearest-neighbour spin arrangement. This effect is used here to monitor the intrachain short-range spin correlations in CuGeO₃ as a function of temperature [1].

I will also present recent time-resolved RIXS data obtained at the SXR beamline of the XFEL LCLS. After photoexciting CuGeO₃ with 266 nm photon pulses, we observe a transient suppression of the ZRS intensity within a few picoseconds. Its recovery is then tracked over hundreds of picoseconds. This allows us to monitor the ultrafast dynamics of short-range spin correlations CuGeO₃.

[1] C. Monney et al., PRL 110, 087403 (2013)