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 quantum effects that arise from electron-lattice dephasing in molecules and crystals for next-generation devices.

中文翻译：

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用超快电子衍射同时探测1T-TaSeTe中光激发引起的电子晶格移相

在非平衡过程中同时探测材料中的电子和晶格在技术上具有挑战性，从而确定它们之间的相关性。在这里，在电荷密度波（CDW）材料上拍摄的一组超快电子衍射图中$\mathrm{1个}Ť$-TaSeTe，我们发现衍射强度测量中的时间偏移是散射角的函数。借助动力学模型和理论计算，我们证明了超快电子同时探测了价电子和晶格动力学过程，从而进行了时移测量。我们的结果清楚地表明，CDW不仅是存在于晶体中的周期性晶格变形的结果$\mathrm{1个}Ť$-TaSeTe，但具有重要的电子起源。该方法展示了一种研究下一代设备分子和晶体中电子晶格移相产生的许多量子效应的方法。