Performance prediction of nanoscale thermal cloak by molecular dynamics
J Zhang and HC Zhang and HM Wang and CZ Xu and Q Wang, APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING, 127, 790 (2021).
Recently, the unique functions of the nanoscale thermal cloak have aroused the interest of researchers. They use graphene and silicon film to design a chemically functionalized and an in situ annealed nanoscale thermal cloak, respectively. In addition, the phenomenon of nanoscale cloaking is observed for the first time through an ion irradiation platform. However, these design methods are relatively complicated and only explore the performance at a constant temperature boundary, which greatly limits their engineering applications. Periodic depression of silicon film can also reduce thermal conductivity, and a lot of research has been done, but no thermal cloak has been designed yet. Therefore, in this paper, we first build a rectangular cloak in this way to prove that it can produce cloaking. Then, we extend this approach through building a depressed ring nanoscale thermal cloak by the classical thermal cloak model, exploring its dynamic response and investigating the effect of depression depth on its cloaking performance. Besides, we obtain the response temperature and ratio of thermal cloaking as a function of depression depth. Finally, the potential cloaking mechanism of the constructed thermal cloak is investigated by calculating and analyzing the phonon density of states and phonon mode participation rate within the structure. We find that the main reason for the decrease in the thermal conductivity of the functional region is phonon localization. This study aims to facilitate the engineering application of nanoscale thermal cloaks by exploring a new design approach and provide a reference for the development of other nanoscale devices.
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