Fig. 2: Photo-induced changes of the XRD from a thin flake of 1T-TaS₂ .

Reciprocal space maps parallel to the hk0-plane (integration thickness perpendicular to the plane: δl = 2∕3 r.l.u.) for the NCCDW at room temperature (a), the CCDW at T = 4 K (b) and the photo-induced HCDW at the same temperature T = 4 K. The characteristic occurrence of strong higher-order superlattice reflections due to the in-plane discommensurations network is clearly observable for the NCCDW (a) and the HCDW (c). Reciprocal space maps parallel to the h0l-plane (integration thickness perpendicular to the plane: δk = 0.3 r.l.u.) are shown in d–f for NCCDW, CCDW, and HCDW, respectively. The extracted intensity distribution of the superlattice reflections along the l-direction clearly shows the well-defined sharp spots for the NCCDW (g), the characteristic diffuse double-peak feature for the CCDW (h) and the vanishing of the diffuse scattering for the photo-induced HCDW. The black bars in g, h, and i indicate the full width at half maximum of a typical Bragg peak.