带串联三角形孔的氮化硼纳米带的热整流效应

Thermal Rectification in Boron Nitride Nanoribbons With Triangular Vacancy Defects in Series

采用非平衡分子动力学方法,模拟了含有三角形孔的氮化硼纳米带(BNNR)不同方向的热导率和热整流效应;采用声子波包方法,分析了热整流机理;并结合正交试验设计,考察了温度、串联孔数和三角形孔边长的影响。研究结果表明;带孔纳米带的热导率低于完整纳米带;氮化硼纳米带从三角形孔的顶角到底边的导热能力强于相反方向的,三角形结构所造成的声子透射率差异是产生整流效应的主要原因;随着孔数的增多,热整流效应增强,但由于多孔界面间相互反射的影响,其增强趋势逐渐减缓;随着孔边长的增大,界面散射影响增加,热整流效应明显增强;孔边长因素比孔数对热整流效应的影响更大。

We investigated thermal transport and thermal rectification in the boron nitride nanorib- bons（BNNRs） with triangular vacancy defects in series, by using non-equilibrium molecular dynamics simulation. The analysis was performed on the related phonon wave-packet. Furthermore, the orthogonal test was carried out to compare factors such as the number and the size of defects. It turns out that triangular vacancy defects would cause reduction in the thermal conductivity and significant thermal rectification in the nanoribbons. The thermal conductivity in the case of heat transferred from the triangle apex to its base is always higher than that in the reverse direction. This is attributed to the phonon interface scattering and the difference in phonon transmissivity caused by the asymmetric structure. The thermal rectification coefficient enhances with the increase in the number or/and the size of defects. But the defect size is more effective than its number on the thermal rectification.