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

Cornell Affiliated Author(s)

Author

C.J.R. Duncan
M. Kaemingk
W.H. Li
M.B. Andorf
A.C. Bartnik
A. Galdi
M. Gordon
C.A. Pennington
I.V. Bazarov
H.J. Zeng
F. Liu
D. Luo
A. Sood
A.M. Lindenberg
M.W. Tate
D.A. Muller
J. Thom-Levy
S.M. Gruner
J.M. Maxson

Abstract

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.

Date Published

Journal

Elsevier

Volume

253

Number of Pages

113771+

ISBN Number

0304-3991

URL

https://www.sciencedirect.com/science/article/pii/S0304399123000888

DOI

https://doi.org/10.1016/j.ultramic.2023.113771

Group (Lab)

Sol M. Gruner Group

Funding Source

DE-SC0020144
DE-SC0017631
PHY-1549132
DE-AC02-76SF00515

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