Regensburg 2019 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 80: Ultrafast Electron Dynamics at Surfaces and Interfaces I
O 80.5: Vortrag
Donnerstag, 4. April 2019, 11:30–11:45, H16
Real-space order parameter mapping using ultrafast transmission electron microscopy — •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 (UTEM) allows for resolving femtosecond dynamics in heterogeneous materials using imaging, diffraction, and spectroscopy [1].
The pulsed electron source of the Göttingen UTEM project employs linear photoemission from a nanoscopic Schottky emitter, delivering highly coherent electron pulses with down to 200 fs pulse duration, 0.6 eV energy width, and sub-1 nm focused beam diameter [2].
Here, we 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.
[1] A. H. Zewail, Science 328, 187 (2010).
[2] A. Feist, Th. Danz et al., Ultramicroscopy 176, 63 (2017).