Ultrafast nanoimaging of the order parameter in a structural phase transition
Ultrafast nanoimaging of the order parameter in a structural phase transition
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DOI：
10.1126/science.abd2774
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发表时间：
2021-01-22
期刊：
影响因子：
56.9
通讯作者：
Ropers, Claus
中科院分区：
文献类型：
--
作者：
Danz, Thomas;Domroese, Till;Ropers, Claus
了解材料和设备中的微观过程，可以通过光切换需要实验访问纳米长度和飞秒时间尺度上的动力学。在这里，我们介绍了超快暗场电子显微镜映射整个结构相变的序参数。我们使用超短激光脉冲局部激发1 T-TaS 2（1 T-多型二硫化钽）薄膜和图像的瞬态样品的超短电子脉冲。一个定制的暗场孔径阵列使我们能够跟踪电荷密度波域的演变，同时飞秒的时间和5纳米的空间分辨率的材料，阐明弛豫途径和畴壁动力学。选择性对比度增强的独特优势将激发未来超快透射电子显微镜中的光束整形技术。
Understanding microscopic processes in materials and devices that can be switched by light requires experimental access to dynamics on nanometer length and femtosecond time scales. Here, we introduce ultrafast dark-field electron microscopy to map the order parameter across a structural phase transition. We use ultrashort laser pulses to locally excite a 1T-TaS2 (1T-polytype of tantalum disulfide) thin film and image the transient state of the specimen by ultrashort electron pulses. A tailored dark-field aperture array allows us to track the evolution of charge-density wave domains in the material with simultaneous femtosecond temporal and 5-nanometer spatial resolution, elucidating relaxation pathways and domain wall dynamics. The distinctive benefits of selective contrast enhancement will inspire future beam-shaping technology in ultrafast transmission electron microscopy.