A practical approach to determine the handedness of chiral carbon nanotubes by electron diffraction

Abstract

A practical procedure has been proposed to determine the handedness of a carbon nanotube from its electron diffraction patterns. When a nanotube is twisted, the diffraction layer line spacings change, although the intensity distribution on the layer lines stays unchanged. The handedness can be assigned by observing the directions in which the principal layer lines shift under known direction of twisting and the twisting angle can be derived directly from the ratio of the diffraction layer line spacings. Simulated electron diffraction patterns of a carbon nanotube twisted both clockwise and counterclockwise are also presented as an example to corroborate the theoretical analysis.