Dresden 2020 – scientific programme
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MA: Fachverband Magnetismus
MA 26: Ultrafast Electron Dynamics II (joint session O/MA)
MA 26.3: Talk
Tuesday, March 17, 2020, 11:15–11:30, WIL B321
Ultrafast nano-imaging of the order parameter in a structural phase transition — •Thomas Danz, Till Domröse, and Claus Ropers — 4th Physical Institute – Solids and Nanostructures, University of Göttingen, Germany
Over the past decades, ultrafast optical techniques have considerably shaped our understanding of homogeneous materials, while transmission electron microscopy has greatly contributed to elucidating atomic structures and compositions on the sub-nanometer scale. Combining these concepts, ultrafast transmission electron microscopy allows for resolving femtosecond dynamics in heterogeneous materials using imaging, diffraction, and spectroscopy [1].
Here, we employ the Göttingen Ultrafast Transmission Electron Microscope (UTEM) [2] to demonstrate the ultrafast real-space mapping of the order parameter for a charge-density wave phase transition in the correlated material 1T-TaS2. Specifically, we track the evolution of domain patterns on femtosecond to picosecond time and nanometer length scales, extracting characteristic observables not accessible by ultrafast electron or x-ray diffraction.
Additionally, we show that prominent features in the spatio-temporal domain evolution can be modeled in a time-dependent Ginzburg-Landau approach, allowing us to distinguish different regimes of the observed dynamics.
[1] A. H. Zewail, Science 328, 187 (2010).
[2] A. Feist, Th. Danz et al., Ultramicroscopy 176, 63 (2017).