Nanowire transformation into long-range-ordered nanocluster chains controlled by thermocapillarity

Capillarity-driven surface-free-energy minimization may lead to morphological changes of nanowires (NWs), e.g. their decay into chains of nanoclusters (NCs) by the Rayleigh instability. At the nano-scale, such capillary effects are more pronounced than in macroscopic systems due to the large surface-to-volume ratio. However, the capillary-driven NW decay is subject to increasing fluctuations with decreasing dimensions. This might prevent the formation of NC chains with long-range order which is needed for potential applications (e.g. in nanophotonics as light guides). We predict a novel method to fabricate long-range-ordered NC chains by decay of NWs under the control of an external temperature field. The prediction is based on the temperature dependence of surface tension causing thermocapillary effects. Surface tension gradients trigger atomic migration from hot to cold regions. Thus, long-range-order of NC chains may be achieved by a weak periodic temperature field along the NW. Such a temp. profile might be realized by a standing surface-plasmon-polariton wave. Here, a feasibility evaluation of the prediction will be presented which is based on computer experiments. The NW decay with and without external temperature fields was examined by kinetic Monte Carlo simulations. Just a small, symmetry-breaking periodic temperature field is needed to control long-range-order. In practice, the field must be stronger than thermally induced fluctuations along the NW, as is discussed.