Abstract:It has been technically challenging to concurrently probe the electrons and the lattices in materials during nonequilibrium processes, allowing their correlations to be determined. Here, in a single set of ultrafast electron diffraction patterns taken on the charge-density-wave (CDW) material 1T -TaSeTe, we discover a temporal shift in the diffraction intensity measurements as a function of scattering angle. With the help of dynamic models and theoretical calculations, we show that the ultrafast electrons probe both the valence-electron and lattice dynamic processes, resulting in the temporal shift measurements. Our results demonstrate unambiguously that the CDW is not merely a result of the periodic lattice deformation ever present in 1T -TaSeTe but has significant electronic origin. This method demonstrates an approach for studying many novel properties that arise from electron-lattice dephasing in molecules and crystals for next-generation devices.
Co-author:Li, J.; Li, J.; Sun, K.; Wu, L.; Li, R.; Yang, J.; Shen, X.; Wang, X.; Luo, H.; Cava, R. J.; Robinson, I. K.; Jin, X.; Yin, W-G.; Zhu, Y.; and Tao J
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