2022 Fiscal Year Annual Research Report
Control the transport of phonon in a broad frequency range in low dimensional materials
| Project/Area Number |
21J21382
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| Allocation Type | Single-year Grants |
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| Research Institution | The University of Tokyo |
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Principal Investigator |
DING WENYANG 東京大学, 工学系研究科, 特別研究員(DC1)
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| Project Period (FY) |
2021-04-28 – 2024-03-31
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| Keywords | VdW heterostructures / Thermal conductivity / Phonon incident angle |
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| Outline of Annual Research Achievements |
VdW heterostructures are an ideal candidate to realize low thermal conductivity in their through-thickness direction due to its weak interlayer interactions and prominent disorder by alternating stacking orders. Herein, for the first time, heat conduction in vdW heterostructures are resolved to the level of individual phonon polarizations, whose incident angles are utilized to elucidate the role that phonon
interference and phonon tunneling play in vdW heterostructures.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
In my original plan, the mode-resolved atomistic Green's function will be performed to understand the underlying physical mechanism for the significantly suppressed thermal conductivity of the optimized van der Waals graphene-WS2 heterostructure. Now not only the mode-resolved atomistic Green's function is successfully imposed on heterostructure, but also a conclusion that the ultralow thermal conductivity of van der Waals graphene-WS2 heterostructure is due to the suppression of oblique incident phonons is derived.
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| Strategy for Future Research Activity |
1. Since Bayesian optimization can only obtain the individual optimized heterostructure with ultralow thermal conductivity, a new machine learning method called SLEPA which can derive the distribution of thermal conductivity and their corresponding heterostructure is performed.
2. Now only graphene and WS2 are utilized to construct heterostructure, in the future plan, another new material is added (total three materials) to construct heterostructure to explore the possibility of getting even smaller thermal conductivity.
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