Carbon Nanotube Electronic Displacement Encoder with Sub-Nanometer Resolution...

Electric conductance of a telescope double-walled carbon nanotube oscillates as a function of telescoping distance. The period of such oscillation is one half of the lattice constant of graphene, $a/2 = 0.123$nm, instead of the lattice constant $a$ as expected. The halving of the period results from the combination of the periodic interlayer lattice alignment and the occurrence of antiresonance. When combined with the periodicity in the energy space at a fixed displacement, the telescopic displacement can be reliably and accurately determined to the sub-nanometer resolution. This effect can be used to design an electronic displacement encoder.