Coherent electron transport in a helical nanotube

• Fano resonance induced by the geometric potential of a helical nanotube is analyzed.
• Symmetry blocking in a bent cylindrical surface is found and proved.
• The transport of double-degenerate mode in a helical nanotube is reminiscent of the Zeeman coupling.
• New plateau in conductance appears for a helical nanotube with suitable length.

The quantum dynamics of carriers bound to helical tube surfaces is investigated in a thin-layer quantization scheme. By numerically solving the open-boundary Schrödinger equation in curvilinear coordinates, geometric effect on the coherent transmission spectra is analysed in the case of single propagating mode as well as multimode. It is shown that, the coiling endows the helical nanotube with different transport properties from a bent cylindrical surface. Fano resonance appears as a purely geometric effect in the conductance, the corresponding energy of quasibound state is obviously influenced by the torsion and length of the nanotube. We also find new plateaus in the conductance. The transport of double-degenerate mode in this geometry is reminiscent of the Zeeman coupling between the magnetic field and spin angular momentum in quasi-one-dimensional structure.