Time-resolved resonant elastic soft X-ray scattering at Pohang Accelerator Laboratory X-ray Free Electron Laser

TL;DR

This paper introduces a new time-resolved resonant soft X-ray scattering endstation at PAL-XFEL, enabling femtosecond-scale investigation of electronic order dynamics in strongly correlated materials.

Contribution

It presents the development and commissioning of a novel tr-RSXS endstation with high temporal resolution at a major X-ray free electron laser facility.

Findings

Achieved ~100 fs time resolution in soft X-ray scattering

Demonstrated temporal dynamics of charge density wave in cuprate superconductor

Enabled new studies of electronic order dynamics in correlated systems

Abstract

Resonant elastic X-ray scattering has been widely employed for exploring complex electronic ordering phenomena, like charge, spin, and orbital order, in particular in strongly correlated electronic systems. In addition, recent developments of pump-probe X-ray scattering allow us to expand the investigation of the temporal dynamics of such orders. Here, we introduce a new time-resolved Resonant Soft X-ray Scattering (tr-RSXS) endstation developed at the Pohang Accelerator Laboratory X-ray Free Electron Laser (PAL-XFEL). This endstation has an optical laser (wavelength of 800 nm plus harmonics) as the pump source. Based on the commissioning results, the tr-RSXS at PAL-XFEL can deliver a soft X-ray probe (400-1300 eV) with a time resolution about ~100 fs without jitter correction. As an example, the temporal dynamics of a charge density wave on a high-temperature cuprate superconductor is demonstrated.