异质结碳纳米管的热整流效率  

Thermal rectification of heterojunction nanotubes

作　　者：温家乐 徐志成[1] 古宇[1] 郑冬琴[1] 钟伟荣[1] 

机构地区：[1]暨南大学物理系,思源实验室,广州510632

出　　处：《物理学报》2015年第21期353-359,共7页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:11004082;11291240477);广东省自然科学基金(批准号:2014 A030313367);中央高校基本科研业务费专项资金(批准号:11614341)资助的课题~~

摘　　要：采用非平衡分子动力学方法,通过分别控制异质结碳纳米管管径、手性和平均温度的方式研究了异质结碳纳米管的热整流效应.研究表明,随着异质结碳纳米管两端几何不对称性的增强,其热整流效率会随之上升,而异质结碳纳米管两端的手性的改变和夹角的大小都会对热整流效率产生一定的影响.热整流效率会随着碳纳米管平均温度的上升而下降.研究异质结碳纳米管热整流效率对于热二极管、碳纳米散热元器件等潜在应用价值有理论指导作用.Using non-equilibrium molecular dynamics method, we have studied the thermal rectification of heterojunction nanotubes（HCNTs）. All of these HCNTs, composed of two 4 nm long carbon nanotubes（CNTs）, only have a pentagonheptagon defects pair. Here the positive direction is defined as the direction where the heat flux flows from the large diameter CNTs to the small diameter CNTs. We have found that the thermal rectification depends on the diameter, the chirality and the temperature.Diameter effect： We fix the diameter on one side and changed it on another side, i.e., the left side of the HCNTs is（3, 3） while the right side of the HCNTs is（n, n）, in which n changes from 4 to 9. It is found that the thermal rectification efficiency of HCNTs increases with n（also with the diameter difference）. If considering the temperature field of（3, 3）–（4,4） HCNTs, one can find that there exists a region near the HCNT where the temperature changes sharply. This region when the flux is positive is similar to that when the flux is negative. However, if taking into consideration the（3, 3）–（9,9） HCNTs, we find that the distribution of temperature field shows different behaviors when the directions of the heat flux are different, and the length of this region becomes longer than（3, 3）–（4, 4）. It can be explained that the thermal rectification is caused by different temperature distributions in HCNTs.Chirality effect： We keep the chirality unchanged on one side of HCNTs and change the chirality of the other side,namely, the chirality of the left side of HCNTs are（3, 3） and the right side are（9, 9）,（11, 7）,（13, 4） and（15, 1）, all of their diameters are close to 4.1 ？. We can find that the intersection angle between two CNTs decreases when the right side of HCNTs changes from（9, 9） to（15, 1）, and the thermal rectification efficiency will be enhanced. It can be explained that the phonon is scattered and absorbed more effectively at the hetero-junction as the i

关 键 词：碳纳米管 异质结 热整流 传热 

分 类 号：TB383.1[一般工业技术—材料科学与工程]