Fig. 3: Distinct photoinduced changes of 2D CDW below and above Tc.
From: Light-induced dimension crossover dictated by excitonic correlations
a, b Left: static electron diffraction patterns along the [0 0 1] zone axis taken at 88 K (a) and 295 K (b). Hexagons denote the 2D projection of the Brillouin zones. Right: photoinduced change in the diffraction intensity at 1 ps pump-probe delay at 88 K (a) and at 0.2 ps delay at 250 K (b). The different time delays are chosen to reflect the distinct timescales of the intensity change at different temperatures (see panel c). All diffraction images were symmetrized for enhanced statistics. The equilibrium patterns share the same color scale while that of the differential patterns is individually adjusted to highlight the feature at the M point. See Supplementary Fig. 8 for a side-by-side comparison of differential patterns at two time delays with the same color scale. c Temporal evolutions of intensity change at the M point at 88 K (red) and 250 K (blue). Intensities are normalized to respective pre-excitation values. Error bars, if larger than the marker size, represent the standard deviation of intensity values prior to excitation. The incident fluence for all panels is 560 μJ/cm2.
