Accessing the earliest electronic response of quantum materials requires combining few-femtosecond time resolution with element specificity and control over temperature. In this work, we introduce a table-top cryogenic ultrafast broadband XUV absorption spectroscopy beamline that spans 22–73 eV, reaches temperatures down to 20 K, and provides sub-50-meV energy resolution with a sub-10-fs instrument response.

Using the van der Waals multiferroic NiI₂ as a benchmark, we resolve temperature-dependent changes across its magnetic phase transitions and track the element-specific response on the femtosecond timescale. The instrument opens a route to studying the initial electronic response and emergence of nonequilibrium states in quantum materials with simultaneous ultrafast, element-specific, and cryogenic sensitivity.

The preprint can be found here: https://arxiv.org/abs/2608.03955