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.