Roughening transition as a driving factor in the formation of self

TL;DR

This study uses Monte Carlo simulations to explore how roughening transitions influence the formation of modulated nanostructures, revealing mechanisms that can be controlled for nanowire synthesis.

Contribution

It demonstrates that roughening transitions drive subcritical modulations in nanowires, offering new insights into their controlled formation and stability.

Findings

Roughening transition causes subcritical modulations in nanowires.

External activation can induce roughening without heating.

Results applicable to BCC and FCC lattice nanostructure synthesis.

Abstract

Based on the Monte Carlo kinetic method, we investigated the formation mechanisms of periodical modulations arising along the length of one-dimensional structures. The evolution of initially cylindrical nanowires/slabs at temperatures lower than their respective melting temperatures can result either in breakup into single nanoclusters or in the formation of stable states with pronounced modulations of cross section. Such configurations, observed in a number of experiments, are excited at wavelengths that are below the critical value for the development of classical Rayleigh instability. We show that the modulation excited in the subcritical mode corresponds to the appearance of roughening transition on the quasi-one-dimensional surface of nanowires/slabs. Since the arise of roughening transition is possible only on certain facets of metals with a given crystal structure, the short-wavelength modulations of one-dimensional systems, as shown in our work, can be realized (i) with the proper orientation of the nanowire/slab axis providing spontaneous appearance of roughening transition on its lateral surface, (ii) by the method of activating the surface diffusion of atoms by external impact (irradiation with an electron beam or contact with a cold plasma), which stimulates roughening transition without significant heating of the nanowire. The results obtained for the cases of BCC and FCC lattices can be used in the controlled synthesis of ordered one-dimensional structures for use in optoelectronics and in ultra-large-scale integrated circuits.