Selective Cap Opening in Carbon Nanotubes Driven by Laser-Induced Coherent Phonons

The possibility of a selective nonequilibrium cap opening of carbon nanotubes as a response to femtosecond laser excitation was demonstrated. It was found that the nonthermal response could induce a desired structural modification on a subpicosecond time scale. By performing molecular dynamics simulation based on a microscopic electronic model, it was shown that the laser induced ultrafast structural changes differed from the thermally induced dimer emissions. It was also shown that ultrafast bond weakening and simultaneous excitation of two coherent phonon modes of different frequencies localized in the spherical caps and cylindrical nanotube body were responsible for the selective cap opening.