径向压缩单壁碳纳米管的力学行为

寻求具有卓越性能而又易于制造的纳米开关是纳米科技界的一个研究热点. 首先基于碳纳米管的结构双稳性提出了一种纳米开关的原型设计, 其由关到开的转换可通过径向压缩实现; 然后利用基于REBO-II作用势的分子动力学模拟, 系统分析了径向压缩单壁碳纳米管的力学行为和不同纳米管的双稳性特征, 给出了一些纳米管双稳性的特征参数, 对于工程设计具有一定的指导意义.

Mechanical behavior of radial compressed single-walled carbon nanotubes

Carbon nanotubes have been proposed as one of the most promising materials in nanoelectrome-chanical systems (NEMS). In this paper, taking advantage of the bistability of single-walled carbon nanotubes, we at first give a prototype design of nanoswitches which can serve as fundamental building blocks for the design of NEMS components or random access memory. The switch may be switched between ON and OFF states by applying electrostatic forces. We then focus on the mechanical behavior of the switch being turned on from off state, that is, a radial compressed single-walled carbon nanotube collapsing into a ribbon-like structure. The molecular dynamics simulation we used is based on second-generation-bond-order potential developed by Brenner. We show that, with the tube diameter increasing from 2 to 5 nm, the energy barrier between the two stable states of a nanotube increases firstly and then decreases. The peak value of energy barrier is approached at the diameter equal to about 3.8 nm. This conclusion is very useful to the potential application of the bistability of carbon nanotubes in NEMS. We also investigate the initial radial elastic modulus of carbon nanotubes and the results show that it is approximately in linear relation with the tube diameter in a double logarithm coordinate system for the tubes with diameters ranging from 1 to 5 nm.