Direct Detection of Ultrafast Nonthermal Charge Density Wave Switching in 1T-TaS₂

Abstract

　We report a grazing-incidence, optical pump–X-ray probe study at BL3 of SACLA, designed to directly resolve the ultrafast nonthermal switching of charge density waves in 1T-TaS₂. While the NC-CDW and C-CDW peaks were measured at 300 K and 80 K respectively, the latter was too weak for temporal analysis, primarily due to icing and geometrical constraints at low temperatures. Our results underscore the necessity of a dedicated cryogenic setup for future ultrafast diffraction studies under these conditions.