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Charge Density Wave (CDW) compounds present an ideal model system to study electron-electron and electron-lattice correlations. These phenomena can experimentally be approached by pump probe spectroscopy, where an intense laser pulse abruptly perturbs the system and a second (light, X-ray, electron) pulse tracks down the different relaxation pathways on the femtosecond (fs) timescale.
We employed femtosecond electron diffraction (FED) and all-optical pump probe experiments on the 2D CDW system 1T-TaS2, studying the order parameter relaxation therein. The data suggest an optically induced suppression of the CDW within ~250 fs, followed by a purely electronic relaxation which is faster than ~100 fs. The order parameter of the CDW however, recovers on a timescale of several picoseconds which can be directly assessed by the FED data and also indirectly by the undertaken all-optical pump probe experiments. |
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