  Molecular dynamics simulation have shown that after initial surface melting,
nanowires can melt via two mechanisms: an interface front moves towards the
wire centre; the growth of an instability at the interface can cause the solid
to pinch-off and breakup. By perturbing a capillary fluctuation model
describing the interface kinetics, we show when each mechanism is preferred and
compare the results to molecular dynamics simulation. A Plateau-Rayleigh-type
of instability is found, and suggests longer nanowires will melt via a
instability mechanism, whereas in shorter nanowires the melting front will move
closer to the centre before the solid pinch-off can initiate. Simulations
support this theory; preferred modes that destabilise the interface are
proportional to the wire length, with longer nanowires preferring to pinch-off
and melt; shorter wires have a more stable interface close to their melting
temperature, and prefer to melt via an interface front that moves towards the
wire centre.
