Quantum conductance of a helically coiled carbon nanotube

Using a π-orbital tight-binding model, we investigate the transport properties of a coiled carbon nanotube (also called carbon nanotube spring), which we construct by connecting carbon nanotubes periodically in three-dimensional (3D) space. The conductance is quantized due to the translational symmetry in the coiled direction. However, the conductance behaviors differ greatly from those of pristine metallic carbon nanotubes but similar to those of carbon nanotube superlattices. We explain that conductance behaviors of the coiled carbon nanotube.