  To investigate cylindrical ultrathin copper nanowires, we performed atomistic
simulations using the steepest descent method. The stable structures of the
cylindrical ultrathin copper nanowires were multi-shell packs composed of
coaxial cylindrical shells with {111}-like surfaces. Semiclassical orbits in a
circle and circular rolling of a triangular network could explain the
structures of the cylindrical ultrathin multi-shell copper nanowires. A
calculation of the angular correlation function and the radial distribution
function for nanowires showed that the structural properties of nanowires
became closer to those of the bulk with increasing nanowire diameter.
