Probing phonon focusing, thermomechanical behavior, and moiré patterns in van der Waals architectures using surface acoustic waves

Autor: Nitish Baradwaj, Anikeya Aditya, Ankit Mishra, Kory Burns, Eric Lang, Jordan A. Hachtel, Khalid Hattar, Assel Aitkaliyeva, Aiichiro Nakano, Priya Vashishta, Rajiv Kalia
Jazyk: angličtina
Rok vydání: 2024
Předmět:
Zdroj: npj Computational Materials, Vol 10, Iss 1, Pp 1-8 (2024)
Druh dokumentu: article
ISSN: 2057-3960
DOI: 10.1038/s41524-024-01315-5
Popis: Abstract Surface acoustic waves (SAWs) propagate along solid-air, solid-liquid, and solid-solid interfaces. Their characteristics depend on the elastic properties of the solid. Combining transmission electron microscopy (TEM) experiments with molecular dynamics (MD) simulations, we probe atomic environments around intrinsic defects that generate SAWs in vertically stacked two-dimensional (2D) bilayers of MoS2. Our joint experimental-simulation study provides insights into SAW-induced structural and dynamical changes and thermomechanical responses of MoS2 bilayers. Using MD simulations, we compute mechanical properties from the SAW velocity and thermal conductivity from thermal diffusion of SAWs. The results for Young’s modulus and thermal conductivity of an MoS2 monolayer are in good agreement with experiments. The presence of defects, such as nanopores which generate SAWs, reduces the thermal conductivity of 2D-MoS2 by an order of magnitude. We also observe dramatic changes in moiré patterns, phonon focusing, and cuspidal structures on 2D-MoS2 layers.
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