Low thermal conductivity of peanut-shaped carbon nanotube and its insensitive response to uniaxial strain
Low thermal conductivity of peanut-shaped carbon nanotube and its insensitive response to uniaxial strain
复制标题
DOI：
10.1088/1361-6528/ab5b2c
复制
发表时间：
2019-11
期刊：
影响因子：
3.5
通讯作者：
Jie Sun;Kunpeng Yuan;Wenyang Zhou;Xiaoliang Zhang;J. Onoe;Y. Kawazoe;Qian Wang
中科院分区：
文献类型：
--
作者：
Jie Sun;Kunpeng Yuan;Wenyang Zhou;Xiaoliang Zhang;J. Onoe;Y. Kawazoe;Qian Wang
基于花生状碳纳米管（PSNT）的实验合成，采用非平衡态分子动力学模拟、晶格动力学和密度泛函理论研究了PSNT（1dp08）的热导率及其对不同应变的响应.我们发现，PSNT的热导率降低了90%以上，相比，碳纳米管，并保持几乎相同，当施加不同的应变，表现出非常不同的行为，从碳纳米管，其中的热导率单调下降，应变的增加。通过声子模计算，我们发现声子群速度、声子寿命和振动失配是导致PSNT热导率低的原因，而热导率对应变不敏感的原因是其声子态密度和群速度对应变不敏感.这些特性赋予了PSNT在热器件中的潜在应用，并为一维碳纳米材料增添了超越传统CNT的新功能。
Motivated by the experimental synthesis of peanut-shaped carbon nanotubes (PSNTs) that combine the novel features of fullerene and carbon nanotubes (CNTs), we study the thermal conductivity of a PSNT (1dp08) and its response to different strains by using non-equilibrium molecular dynamics simulations and lattice dynamics together with density functional theory. We find that the thermal conductivity of the PSNT is reduced by more than 90% as compared to that of CNTs, and remains almost the same when different strains applied, exhibiting very different behaviors from that of CNTs, where the thermal conductivity decreases monotonically with the increase of strain. Through phonon mode calculations, we show that the reduced phonon group velocity, phonon lifetime and the vibrational mismatch are responsible for the low thermal conductivity of the PSNT, and the insensitive response of thermal conductivity to strain is due to the insensitivity of its phonon density of states and group velocity to strain. These features endow the PSNT with the potential applications in thermal devices, and add new features to one-dimensional carbon nanomaterials going beyond conventional CNTs.