Dynamics of Local Chirality
during SWCNT Growth: Armchair
versus Zigzag Nanotubes
- Publication date
- Publisher
Abstract
We present an analysis of the dynamics of single-walled
carbon
nanotube (SWCNT) chirality during growth, using the recently developed
local chirality index (LOCI) method [Kim et al. Phys. Rev. Lett. 2011, 107, 175505] in conjunction with quantum chemical
molecular dynamics (QM/MD) simulations. Using (5,5) and (8,0) SWCNT
fragments attached to an Fe<sub>38</sub> catalyst nanoparticle, growth
was induced by periodically placing carbon atoms at the edge of the
SWCNT. For both armchair and zigzag SWCNTs, QM/MD simulations indicate
that defect healingthe process of defect removal during growthis
a necessary, but not sufficient, condition for chirality-controlled
SWCNT growth. Time-evolution LOCI analysis shows that healing, while
restoring the pristine hexagon structure of the growing SWCNT, also
leads to changes in the local chirality of the SWCNT edge region and
thus of the entire SWCNT itself. In this respect, we show that zigzag
SWCNTs are significantly inferior in maintaining their chirality during
growth compared to armchair SWCNTs