  The effect of nonconservative current-induced forces on the ions in a
defect-free metallic nanowire is investigated using both steady-state
calculations and dynamical simulations. Non-conservative forces were found to
have a major influence on the ion dynamics in these systems, but their role in
increasing the kinetic energy of the ions decreases with increasing system
length. The results illustrate the importance of nonconservative effects in
short nanowires and the scaling of these effects with system size. The
dependence on bias and ion mass can be understood with the help of a simple pen
and paper model. This material highlights the benefit of simple preliminary
steady-state calculations in anticipating aspects of brute-force dynamical
simulations, and provides rule of thumb criteria for the design of stable
quantum wires.
