Ding Wenyang, Ong Zhun-Yong, An Meng, Davier Brice, Hu Shiqian, Ohnishi Masato, Shiomi Junichiro
Department of Mechanical Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-8656, Japan.
Institute of High Performance Computing, Agency for Science, Technology and Research (A*STAR), 1 Fusionopolis Way, #16-16 Connexis, Singapore 138632, Republic of Singapore.
Nano Lett. 2024 Oct 30;24(43):13754-13759. doi: 10.1021/acs.nanolett.4c03930. Epub 2024 Oct 16.
Van der Waals heterostructures have great potential for realizing ultimately low thermal conductivity because defectless interfaces can be constructed at a length scale smaller than the phonon wavelength, allowing modulation of coherent phonon transport. In this Letter, we demonstrate the mechanism for thermal conductivity reduction at a mode-resolved level. The graphene-WS heterostructure with the lowest cross-plane thermal conductivity of 0.048 W/(m·K) is identified from 16,384 candidates by combining Bayesian optimization and molecular dynamics simulations. Then, the angle-resolved phonon transmission is calculated using the mode-resolved atomistic Green's function. The results reveal that the optimal heterostructure nearly completely terminates phonon transport with finite incident angles, owing to the reduced critical incident angle and suppression of phonon tunneling.
范德华异质结构在实现极低热导率方面具有巨大潜力，因为可以在小于声子波长的长度尺度上构建无缺陷界面，从而实现对相干声子输运的调制。在本信函中，我们在模式分辨水平上展示了热导率降低的机制。通过结合贝叶斯优化和分子动力学模拟，从16384个候选结构中确定了具有最低面内热导率0.048W/(m·K)的石墨烯-WS₂异质结构。然后，使用模式分辨原子格林函数计算角度分辨声子透射率。结果表明，由于临界入射角减小和声子隧穿受到抑制，最优异质结构几乎完全终止了有限入射角下的声子输运。
