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Mehran Vaezi

Publications and source records attributed to Mehran Vaezi.

2 recordsLinked to original sources

Formation of nanoribbons by carbon atoms confined in a single-walled carbon nanotube -- A molecular dynamics study

Carbon nanotubes can serve as one-dimensional nanoreactors for the in-tube synthesis of various nanostructures. Experimental observations have shown that chains, inner tubes, or nanoribbons can grow by the thermal decomposition of organic/organometallic molecules encapsulated in carbon nanotubes. The result of the process depends on the temperature, the diameter of the nanotube, and the type and amount of material introduced inside the tube. Nanoribbons are particularly promising materials for nanoelectronics. Motivated by recent experimental results observing the formation of carbon nanoribbons inside carbon nanotubes, molecular dynamics calculations were performed with the open source LAMMPS code to investigate the reactions between carbon atoms confined within a single-walled carbon nanotube. Our results show that the interatomic potentials behave differently in quasi-one-dimensional simulations of nanotube-confined space than in three-dimensional simulations. In particular, the Tersoff potential performs better than the widely used Reactive Force Field potential in describing the formation of carbon nanoribbons inside nanotubes. We also found a temperature window where the nanoribbons were formed with the fewest defects, i.e., with the largest flatness and the most hexagons, which is in agreement with the experimental temperature range.

cond-mat.mtrl-sci

Comparison of Diffusive Motion of C60 on Graphene and Boron Nitride Surfaces

Inspired by macroscale vehicles, many molecular machines have been synthesized yet. Due to the importance of atomic manipulation at the surface, nanocars are of particular interest. Nanocar wheels play a crucial role in their motion. One of the popular candidate for using as a nanocar wheel is C60 molecule. In addition, the investigation of nanocar motion on two dimensional substrates is important due to formation of ripples on surface. Therefore, in this work we study the motion of C60 on graphene and boron nitride monolayer substrates at 300 K. The simulations are conducted by the means of molecular dynamics method. The trajectory of motion shows more displacement range when fullerene is moving on the graphene surface and as a result, it has a greater diffusion coefficient in this case. It has been showed that C60 motion on graphene and boron nitride obey a same super-diffusion regime at 300 K with different anomaly parameters.

physics.chem-ph