Impact of moire superlattice on atomic stress and thermal transport in van der Waals heterostructures

WJ Ren and S Lu and CQ Yu and J He and ZW Zhang and J Chen and G Zhang, APPLIED PHYSICS REVIEWS, 10, 041404 (2023).

DOI: 10.1063/5.0159598

Moire superlattices and their interlayer interactions in van der Waals heterostructures have received surging attention for manipulating the properties of quantum materials. In this work, based on non-equilibrium molecular dynamics simulations, we find that the in-plane thermal conductivity of graphene/hexagonal boron nitride (h-BN) moire superlattices decreases monotonically with the increase in the interlayer rotation angle within the small twisting range. The atomic stress amplitude exhibits the periodic distribution corresponding to a structural moire pattern. Through the in-depth analysis at the atomic level, a competing mechanism between the magnitude and the directional change of the in-plane heat flow has been revealed, and the dominant role of directional change in determining the in-plane thermal conductivity of graphene/h-BN moire superlattices at small rotation angle has also been confirmed. Finally, the monotonic decreasing trend of in-plane thermal conductivity at a small rotation angle is further explained by the reduced low-frequency phonon transmission and the blue shift of the transmission peak as the interlayer rotation angle increases. Our work provides the physical understanding of the moire superlattice effect and a new approach for regulating the thermal conductivity of two-dimensional materials.

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