  Multishell helical gold nanowires (HGNs) suspended between semi-infinite
electrodes are found to exhibit peculiar electron-conduction properties by
first-principles calculations based on the density functional theory. Our
results that the numbers of conduction channels in the HGNs and their
conductances are smaller than those expected from a single-atom-row nanowire
verify the recent experiment. In addition, we obtained a more striking result
that in the cases of thin HGNs, distinct magnetic fields are induced by the
electron current helically flowing around the shells. This finding indicates
that the HGNs can be good candidates for nanometer-scale solenoids.
