Defects creation in Carbon Nanotubes

[cherry]

Hi all, I tried to create defects in Carbon Nanotubes. Here is what I did: First, drop the CNT.vnl into Bulk Builder and repeat it in Z-axis. Then select the atoms to delete or replace them by other element.

Please advise me if this is correct or not, and if we have to do the structure optimization after the defects are created. Thank you very much.

[Nordland]

It depends on what you want, but I will go with saying the best results is always obtained by performing an optimization of the structure.

[cherry]

Thanks a lot. So the defect creation method is correct, right?

[Nordland]

Yes it is a quite good approch to understanding the fundamental behavior of the system. Remember to a reference calculation on the defect-free system.

[zh]

Other issue, one should take care of the defect concentration. That is to say, when one tries to study a single (or isolated defect), usually  the length of carbon nanotube in the simulation should be chosen large enough to eliminate the interaction between defect and its periodic replicas. The script file generated by the "Carbon Nanotube Grower" only include the coordinates of atoms in the primitive unit cell of carbon nanotube. To create a configure with lower defect concentration, one should use the supercell of CNT.

[cherry]

Thank you so much for the suggestions.
Is it possible to perform the annealing simulation for CNT with monovacancy defect?

[zh]

Currently, the molecular dynamic simulation method is not implemented, so one may not perform the annealing simulation.