[24p-F407-1~17] 22.1 Joint Session M "Phonon Engineering"

▼ [24p-F407-4] Aperiodic van der Waals heterostructures with minimum thermal conductivity

〇(D)Wenyang Ding¹, Shiqian Hu², Masato Ohnishi¹, Cheng Shao¹, Bin Xu¹, Junichiro Shiomi¹ (1.Univ. of Tokyo, 2.Yunnan Univ.)

Keywords:vdW heterostructure, Bayesian optimization, phonon localization

Thermal transport in the stacking direction of van der Waals (vdW) heterostructures plays a pivotal role in determining their thermal properties and performance. Here, we perform non-equilibrium molecular dynamics and Bayesian optimization to explore the controllability of thermal transport in vdW graphene-MoS₂ and graphene-WS₂ heterostructure thin films and identify the ultimate heterostructure that gives minimum thermal conductivity, respectively. The identified optimal heterostructures are aperiodic but non-random and exhibit significantly lower thermal conductivity compared with periodic counterparts. The mechanism of the reduction is further studied in terms of distributions of spectral phonon transmissions and eigenmodes, and the results help characterizing the localization of coherent phonons, where the transmissions distribution suggest Anderson type but the superiority of specific non-random structure suggests contribution of Fabry Perot type.