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Abstract
In recent years, nanoscale thermal cloaks have attracted the interest of researchers. Several different types of nanoscale thermal cloak have been developed with their performance been experimentally validated. However, most of the existing design methods are achieved by quenching the crystalline silicon membrane at high temperatures into an amorphous state to reduce the thermal conductivity of the functional region. This method is experimentally realized by ion irradiation, and the means are relatively complicated, which is not conductive to engineering applications. Defect engineering can also reduce thermal conductivity, and a lot of research has been constructed. Therefore, in the present study, we construct a nanoscale thermal cloak by perforating in a perfect silicon film to reduce thermal conductivity and investigate the effects of the number, the size, and the arrangement of holes on the cloaking performance. Results show that the nanoscale thermal cloak designed by the perforating method can also present a good cloaking effect. In addition, we optimize the cloaking performance using the response surface method and obtain the fitting equation for multiple influence factors. Interactions between each two different influence factors are explored. Furthermore, considering that the cloaking effect is generated by the reduction of thermal conductivity due to phonon localization in the functional area, the potential mechanism of the designed cloak is investigated by calculating and analyzing the phonon density of states (PDOS) and phonon mode participation rate (MPR) within the structure. The study intends to facilitate the engineering application of nanoscale thermal cloak by exploring a new design approach and provide a reference for the development of other nanoscale devices.