2022/06/16 by Cameron Duncan, M. Kaemingk, Duncan, C. J. R. +35
Engineering · Materials Science · Physics and Astronomy · #Advanced Chemical Physics Studies #FOS: Physical sciences #Instrumentation and Detectors (physics.ins-det) #Machine Learning in Materials Science #Materials Science (cond-mat.mtrl-sci) #Thermography and Photoacoustic Techniques
paper · pdf · doi:10.48550/arxiv.2206.08404
openalex publication_date 2022/06/16 · openalex created_date 2022/06/22 · openalex updated_date 2026/07/28
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.