Carbon nanotube transmission between linear and rotational motions

The periodic lattice registry of multi-walled carbon nanotubes (MWCNTs) have been exploited for the possibilities of development of nanodevices. This paper studied the telescoping behaviors of double-walled carbon nanotubes (DWCNTs) by atomic-scale finite element and tight-bind Green function methods. It was found that telescoping a DWCNT (e.g., (6,3)/(12,6)) will induce a rotational motion of the inner CNT that has a chirl angle θ (0° < θ < 30°). This telescoping-induced rotational motion does not exist for armchair and zigzag DWCNTs due to the symmetry of CNTs. The rotational angle is completely determined by the chirality of the inner CNT and can be intuitively explained by screw/nut model. The study of transportation property of (6,3)/(12,6) DWCNT shows a periodic variation of electrical conductance with telescope distance. The period is determined by the lattice constant of graphene (0.246 nm) and chirality of the inner CNT. The unique linear/rotational motions transmission and periodic variation of electrical conductance present fascinating opportunities for the engineering of a new class of nanometrology devices, namely, rotational and distance encoder.