Molecular Dynamics Study Of Oscillatory Behavior Of Oscillators Based On Carbon Nanotubes And MoS₂ Nanotubes

With the rapid development of technology,nanotechnology as one of frontier sciences,plays a critical role in the 21 st century.Nanomaterials have been engaged for building several types of nanosized and excellent devices due to their unique properties.Under the current hot research of nano-electromechanical system,we proposed two different materials of nano-oscillators that based on double-walled carbon nanotubes?CNTs?and CNT@MoS₂ nanotube?CNT@MST?in this paper.The oscillation behavior characteristics of oscillators and the influence of some relevant parameters on oscillation behaviors have been investigated using the molecular dynamics method.The main work are organized as follows:?1?A novel approach is presented to improve the oscillatory behavior of oscillators based on double-walled carbon nanotubes containing rotating inner tube that applied with different helical rises.The influence of the helical rise on the oscillatory amplitude,frequency,and stability of inner tubes with different helical rises in armchair@zigzag bitubes is investigated using the molecular dynamics method.O ur simulation results show that the oscillatory behavior is very sensitive to the applied helical rise.The oscillation of the inner tube with h=1 nm is stable and the initial and equilibrium positions match well after 800 ps in the armchair@zigzag bitubes.The simulation results presented here ind icate that a stable and smooth self-excited oscillator can be obtained by choosing an appropriate value of helical rise in oscillator based on double-walled nanotubes.?2?Oscillatory behavior of novel heterogeneous oscillators composed of CNT@MST is investigated for the first time,by using the methods of classical molecular dynamics.A smooth and stable oscillator with a frequency reaching gigahertz is obtained based on a double-walled CNT@MST hetero-nanotube for a wide range of gap widths of 0.289nm⁰.681 nm,indicating that the proposed oscillators perform much better than those built from double-walled carbon nanotubes that require a narrow range of gap widths.In addition,CNT@MST oscillators containing different inner and outer tube chirality more suited to act as a nano-oscillator with low dissipated oscillation.?3?Molecular dynamics simulations of self-excited oscillation behavior of double-walled CNT@MST-based oscillator with a rotating inner tube is first performed.Simulation results show that the stable oscillation can still sustain and the oscillation frequency can reach gigahertz for the hetero CNT@MST containing an inner tube with an initial rotating rate in range from 5 GHz to 500 GHz,which perform a stronger advantage over the self-excited rotating oscillators that are built from double-walled carbon nanotubes due to the poor oscillation performance.The influence of the system temperature on the oscillatory behavior of inner tube in the CNT@MST bitubes is also investigated.The results show that the oscillation amplitude and frequency of the inner tube increases with temperature increasing when the system temperature below 300 K,but the oscillation of the inner tube is extremely unstable if the temperature reach to 300 K.