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Multi-scale time-resolved electron diffraction: A case study in moiré materials

2023; Elsevier BV; Volume: 253; Linguagem: Inglês

10.1016/j.ultramic.2023.113771

1879-2723

Cameron Duncan, M. Kaemingk, William Li, Matthew Andorf, Adam Bartnik, Alice Galdi, M. Gordon, C. A. Pennington, Ivan Bazarov, Helen J. Zeng, F. Liu, Duan Luo, Aditya Sood, Aaron M. Lindenberg, Mark W. Täte, David A. Muller, Julia Thom-Levy, Sol M. Grüner, Jared Maxson,

Ga2O3 and related materials

Ultrafast-optical-pump - structural-probe measurements, including ultrafast electron and x-ray scattering, provide direct experimental access to the fundamental timescales of atomic motion, and are thus foundational techniques for studying matter out of equilibrium. High-performance detectors are needed in scattering experiments to obtain maximum scientific value from every probe particle. We deploy a hybrid pixel array direct electron detector to perform ultrafast electron diffraction experiments on a WSe2/MoSe2 2D heterobilayer, resolving the weak features of diffuse scattering and moiré superlattice structure without saturating the zero order peak. Enabled by the detector's high frame rate, we show that a chopping technique provides diffraction difference images with signal-to-noise at the shot noise limit. Finally, we demonstrate that a fast detector frame rate coupled with a high repetition rate probe can provide continuous time resolution from femtoseconds to seconds, enabling us to perform a scanning ultrafast electron diffraction experiment that maps thermal transport in WSe2/MoSe2 and resolves distinct diffusion mechanisms in space and time.